Quinolizidinone carboxamide  M1 receptor positive allosteric modulators

ABSTRACT

The present invention is directed to compounds of formula (I) which are M1 receptor positive allosteric modulators and that are useful in the treatment of diseases in which the M1 receptor is involved, such as Alzheimer&#39;s disease, schizophrenia, pain or sleep disorders. The invention is also directed to pharmaceutical compositions comprising the compounds, and to the use of the compounds and compositions in the treatment of diseases mediated by the M1 receptor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No. PCT/US2010/056652 filed on Nov. 15, 2010, which claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 61/263,090, filed Nov. 20, 2009.

FIELD OF THE INVENTION

The invention is directed to a class of quinolizidinone carboxamide compounds, their salts, pharmaceutical compositions comprising them and their use in therapy of the human body. In particular, the invention is directed to a class of quinolizidinone carboxamide compounds which are muscarinic M1 receptor positive allosteric modulators, and hence are useful in the treatment of Alzheimer's Disease and other diseases Mediated by the muscarinic M1 receptor.

BACKGROUND OF THE INVENTION

Alzheimer's Disease is a common neurodegenerative disease affecting the elderly, resulting in progressive memory impairment, loss of language and visuospatial skills, and behavior deficits. Characteristics of the disease include degeneration of cholinergic neurons in the cerebral cortex, hippocampus, basal forebrain, and other regions of the brain, neurofibrillary tangles, and accumulation of the amyloid β peptide (Aβ). Aβ is a 39-43 amino acid produced in the brain by processing of the beta-amyloid precursor protein (APP) by the beta-amyloid protein cleaving enzyme (“beta secretase” or “BACE”) and gamma-secretase. The processing leads to accumulation of Aβ in the brain.

Cholinergic neurotransmission involves the binding of acetylcholine either to the nicotinic acetylcholine receptor (nAChR) or to the muscarinic acetylcholine receptor (mAChR). It has been hypothesized that cholinergic hypofunction contributes to the cognitive deficits of patients suffering from Alzheimer's Disease. Consequently, acetyl cholinesterase inhibitors, which inhibit acetylcholine hydrolysis, have been approved in the United States for use in the treatment of the cognitive impairments of Alzheimer's Disease patients. While acetyl cholinesterase inhibitors have provided some cognitive enhancement in Alzheimer's Disease patients, the therapy has not been shown to change the underlying disease pathology.

A second potential pharmacotherapeutic target to counteract cholinergic hypofunction is the activation of muscarinic receptors. Muscarinic receptors are prevalent throughout the body. Five distinct muscarinic receptors (M1-M5) have been identified in mammals. In the central nervous system, muscarinic receptors are involved in cognitive, behavior, sensory, motor and autonomic functions. The muscarinic M1 receptor, which is prevalent in the cerebral cortex, hippocampus and striatum, has been found to have a major role in cognitive processing and is believed to have a role in the pathophysiology of Alzheimer's Disease. See Eglen et al, TRENDS in Pharmacological Sciences, 2001, 22:8, 409-414. In addition, unlike acetyl cholinesterase inhibitors, which are known to provide only symptomatic treatment, M1 agonists also have the potential to treat the underlying disease mechanism of Alzheimer's Disease. The cholinergic hypothesis of Alzheimer's Disease is linked to both β-amyloid and hyperphosphorylated tau protein. Formation of β-amyloid may impair the coupling of the muscarinic receptor with G-proteins. Stimulation of the M1 muscarinic receptor has been shown to increase formation of the neuroprotective αAPPs fragment, thereby preventing the formation of the Aβ peptide. Thus, M1 agonists may alter APP processing and enhance αAPPs secretion. See Fisher, Jpn J Pharmacol, 2000, 84:101-112 However, M1 ligands which have been developed and studied for Alzheimer's Disease have produced side effects common to other muscarinic receptor ligands, such as sweating, nausea and diarrhea. see Spalding et al, Mol Pharmacol, 2002, 61:6, 1297-1302.

The muscarinic receptors are known to contain one or more allosteric sites, which may alter the affinity with which muscarinic ligands bind to the primary binding or orthosteric sites. See, e.g., S. Lazareno et al, Mol Pharmacol, 2002, 62:6, 1491-1505; S. Lazareno et al, Mol Pharmacol, 2000, 58, 194-207.

Thus, the compounds of the invention, which are muscarinic M1 receptor positive allosteric modulators, are believed to be useful in the treatment of Alzheimer's Disease and other diseases mediated by the muscarinic M1 receptor.

SUMMARY OF THE INVENTION

The present invention is directed to quinolizidinone carboxamide compounds of generic formula (I)

or a pharmaceutically acceptable salt thereof, which is useful as an M1 receptor positive allosteric modulator.

The invention is further directed to methods of treating a patient (preferably a human) for diseases or disorders in which the M1 receptor is involved, such as Alzheimer's disease, cognitive impairment, schizophrenia, pain disorders and sleep disorders, by administering to the patient a therapeutically effective amount of a compound of general formula (I), or a pharmaceutically acceptable salt thereof. The invention is also directed to pharmaceutical compositions, which include an effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, and the use of the compounds and pharmaceutical compositions of the invention in the treatment of such diseases.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the invention is directed to quinolizidinone carboxamide compounds of general formula (I)

and pharmaceutically acceptable salts thereof, wherein R¹ is selected from the group consisting of

-   -   (1) hydrogen, or     -   (2) —C₁₋₆ alkyl,         R² is selected from the group consisting of     -   (1) hydrogen,     -   (2) —C₁₋₆ alkyl,     -   (3) —C₂₋₆ alkenyl,     -   (4) —OC₁₋₆ alkyl,     -   (5) —C₃₋₈ cycloalkyl,     -   (6) —C₅₋₈ cycloalkenyl,     -   (7) a heterocyclic group having 4 to 8 ring atoms selected from         C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N,         N→O, SO₂ or S,     -   (8) heteroaryl, which is an aromatic cyclic or polycyclic group,         having from five to twelve ring atoms, said ring atoms selected         from C, O, N, N→O, C(═O) or S, at least one of which is O, N, or         S, or     -   (9) —C₆₋₁₀ aryl,     -   wherein the alkyl, cycloalkyl, cycloalkenyl, heterocyclic,         heteroaryl or aryl R2 moiety is optionally substituted by one or         more         -   (a) halogen,         -   (b) hydroxyl,         -   (c) —C₁₋₆ alkyl,         -   (d) —O—C₁₋₆ alkyl,         -   (e) —C₃₋₈ cycloalkyl,         -   (f) —C₆₋₁₀ aryl,         -   (g) heteroaryl, which is an aromatic cyclic or polycyclic             group, having from five to twelve ring atoms, said ring             atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least             one of which is O, N, N→O, SO₂ or S, or         -   (h) —(C═O)—C₁₋₆ alkyl,         -   (i) —NR^(A)R^(B), wherein R^(A) and R^(B) are selected from             the group consisting of             -   (i) hydrogen, or             -   (ii) —C₁₋₆ alkyl,         -   or R^(A) and R^(B) are linked together with the nitrogen to             which they are attached to form a 4-6 membered carbocyclic             ring, wherein one or two of the ring carbon atoms is             optionally replaced by a nitrogen, oxygen or sulfur, and the             ring is optionally substituted with one or more             -   (i) halogen,             -   (ii) hydroxyl,             -   (iii) C₁₋₆ alkyl,             -   (iv) —O—C₁₋₆ alkyl,             -   (v) —C(═O)—(O)_(n)—C₁₋₆ alkyl,                 or R¹ and R² are linked together with the nitrogen to                 which they are both attached to form a 4-8 membered                 saturated or unsaturated carbocyclic ring, wherein one                 or two of the ring carbon atoms is replaced by a                 nitrogen, oxygen or sulfur, and the carbocyclic is                 optionally substituted with one or more     -   (a) halogen,     -   (b) hydroxyl,     -   (c) —C₁₋₆ alkyl,     -   (d) —O—C₁₋₆ alkyl,     -   (e) —C₃₋₈ cycloalkyl,     -   (f) —C₆₋₁₀ aryl,     -   (g) heteroaryl, which is an aromatic cyclic or polycyclic group,         having from five to twelve ring atoms, said ring atoms selected         from C, O, N, N→O, C(═O) or S, at least one of which is O, N,         N→O or S, or     -   (h) —(C═O)—C₁₋₆ alkyl;         R³ is optionally present at one or more of the phenyl moiety C         atoms, and is selected from the group consisting of     -   (1) —C₁₋₆ alkyl,     -   (2) —OC₁₋₆ alkyl, or     -   (3) halogen;         R⁴ is selected from the group consisting of     -   (1) a heterocyclic group having 4 to S ring atoms selected from         C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N,         N→O, SO₂ or S,     -   (2) heteroaryl, which is an aromatic cyclic or polycyclic group,         having from five to twelve ring atoms, said ring atoms selected         from C, O, N, N→O, C(═O) or S, at least one of which is O, N,         N→O or S,     -   (3) —C₃₋₈ cycloalkyl,     -   (4) —C₅₋₈ cycloalkenyl, or     -   (5) —C₆₋₁₀ aryl, or     -   wherein the heterocyclic, heteroaryl or aryl moiety is         optionally substituted with one or more         -   (a) halogen,         -   (b) hydroxyl,         -   (c) —C₁₋₆ alkyl,         -   (d) —O—C₁₋₆ alkyl,         -   (e) —C₃₋₈ cycloalkyl,         -   (f) —C₆₋₁₀ aryl,         -   (g) heteroaryl, which is an aromatic cyclic or polycyclic             group, having from five to twelve ring atoms, said ring             atoms selected from C, O, N, N→O, C(═O) or S, at least one             of which is O, N, N→O or S, or         -   wherein the alkyl, cycloalkyl, aryl or heteroaryl moiety is             optionally substituted with one or more             -   (i) halogen,             -   (ii) hydroxyl,             -   (iii) —C₁₋₆ alkyl, or             -   (iv) —O—C₁₋₆ alkyl.

In particular embodiments of compounds of formula (I), R¹ is hydrogen. In other embodiments, R¹ is C₁₋₆ alkyl (preferably methyl or ethyl).

In particular embodiments of compounds of formula (I), R² is —C₃₋₈ cycloalkyl. Suitable cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.

In other embodiments of compounds of formula (I), R² is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heterocyclic groups include tetrahydropyran, piperidine, piperazine, tetrahydropyrrole, morpholine

In other embodiments of compounds of formula (I), R² is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S. Suitable heteroaryl groups include pyridyl, triazolyl, tetrazolyl and tetrahydroquinolinyl.

In other embodiments of compounds of formula (I), R² is C₆₋₁₀ aryl (for example, phenyl).

In other embodiments of compounds of formula (I), or R¹ and R² are linked together with the nitrogen to which they are both attached to form a 4-8 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur. Suitable carbocyclic rings include

In particular embodiments of compounds of formula (I), R³ is absent. In other embodiments of compounds of formula (I), R³ is present at one or more of the phenyl moiety C atoms, and is selected from the group consisting of

-   -   (1) —C₁₋₆ alkyl (preferably methyl),     -   (2) —OC₁₋₆ alkyl (preferably methoxy), or     -   (3) halogen.

In particular embodiments, R³ is absent or is methyl at the following position:

In particular embodiments of compounds of formula (I), R⁴ is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heterocyclic groups include piperidine, piperazines and oxopiperazine. In some embodiments, R⁴ is an N-linked heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S.

In other embodiments of compounds of formula (I), R⁴ is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heteroaryl groups include tetrahydroisoquinoline and pyridyl,

In other embodiments of compounds of formula (I), R⁴ is —C₆₋₁₀ aryl (for example phenyl).

In certain embodiments, the compounds of formula (I) are compounds of formula (II)

and pharmaceutically acceptable salts thereof, wherein R³ and R⁴ are as described above.

In particular embodiments of compounds of formula (II), R³ is absent. In other embodiments of compounds of formula (II), R³ is present at one or more of the phenyl moiety C atoms, and is selected from the group consisting of

-   -   (1) —C₁₋₆ alkyl (preferably methyl),     -   (2) —OC₁₋₆ alkyl (preferably methoxy), or     -   (3) halogen.

In particular embodiments of compounds of formula (I), R⁴ is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heterocyclic groups include piperidine, piperazines and oxopiperazine. In some embodiments, R⁴ is an N-linked heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S.

In other embodiments of compounds of formula (I), R⁴ is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heteroaryl groups include tetrahydroisoquinoline and pyridyl.

In other embodiments of compounds of formula (I), R⁴ is —C₆₋₁₀ aryl (for example phenyl)

In certain embodiments, the compounds of formula (I) are compounds of formula (III)

and pharmaceutically acceptable salts thereof, wherein R¹, R² and R³ are as described above, and R⁶ is selected from the group consisting of

-   -   (1) halogen,     -   (2) hydroxyl,     -   (3) —C₁₋₆ alkyl,     -   (4) —O—C₁₋₆ alkyl,     -   (5) —C₃₋₈ cycloalkyl,     -   (6) —C₆₋₁₀ aryl,     -   (7) heteroaryl, which is an aromatic cyclic or polycyclic group,         having from five to twelve ring atoms, said ring atoms selected         from C, O, N, N→O, C(═O) or S, at least one of which is O, N,         N→O or 5,     -   wherein the alkyl, cycloalkyl, aryl or heteroaryl moiety is         optionally substituted with one or more         -   (a) halogen,         -   (b) hydroxyl,         -   (c) —C₁₋₆ alkyl,         -   (d) —O—C₁₋₆ alkyl.

In particular embodiments of compounds of formula (III), R⁶ is

-   -   (1) —C₆₋₁₀ aryl (suitably phenyl), or     -   (2) heteroaryl, which is an aromatic cyclic or polycyclic group,         having from five to twelve ring atoms, said ring atoms selected         from C, O, N, N→O, C(═O) or S, at least one of which is O, N,         N→O or S. Suitable heteroaryl groups include pyridyl and         pyrazolyl, benzofuran, benzothiazolyl,     -   wherein the aryl or heteroaryl moiety is optionally substituted         with one or more         -   (a) halogen,         -   (b) hydroxyl,         -   (c) —C₁₋₆ alkyl (for example, methyl or ethyl),         -   (d) —O—C₁₋₆ alkyl (for example, methoxy),         -   (e) —CN.         -   wherein the alkyl moiety is optionally substituted with one             or more halogen (suitably fluoro or bromo).

In particular embodiments of compounds of formula (I), R¹ is hydrogen. In other embodiments, R¹ is C₁₋₆ alkyl (preferably methyl or ethyl).

In particular embodiments of compounds of formula (I), R² is —C₃₋₈ cycloalkyl.

Suitable cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

In other embodiments of compounds of formula (I), R² is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heterocyclic groups include tetrahydropyran, piperidine, piperazine, tetrahydropyrrole and morpholine.

In other embodiments of compounds of formula (I), R² is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S. Suitable heteroaryl groups include pyridyl, triazolyl, tetrazolyl and tetrahydroquinolinyl.

In other embodiments of compounds of formula (I), R² is C₆₋₁₀ aryl (for example, phenyl).

In other embodiments of compounds of formula (I), or R¹ and R² are linked together with the nitrogen to which they are both attached to form a 4-8 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur.

In particular embodiments of compounds of formula (I), R³ is absent. In other embodiments of compounds of formula (I), R³ is present at one or more of the phenyl moiety C atoms, and is selected from the group consisting of

-   -   (1) —C₁₋₆ alkyl (preferably methyl),     -   (2) —OC₁₋₆ alkyl (preferably methoxy), or     -   (3) halogen.

Specific embodiments of formula (I) are described herein as Examples, as set forth below:

-   1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide; -   1-[(5-Bromopyridin-2-yl)methyl]-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   N-[(1S,2S)-2-Hydroxycyclohexyl]-1-{[5-(1-methyl-1H-pyrazol-4-yl)pyridine-2-yl]methyl}-4-oxo-4H-quinolizine-3-carboxamide; -   N-[(1S,2S)-2-Hydroxycyclohexyl]-4-oxo-1-{[5-(1H-pyrazol-1-yl)pyridine-2-yl]methyl}-4H-quinolizine-3-carboxamide; -   1-({4-[6-(Difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   N-[(1S,2S)-2-Hydroxycyclohexyl]-1-{[4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazin-1-yl]methyl}-4-oxo-4H-quinolizine-3-carboxylate; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(3R,4R)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-[(4-Cyano-4-phenylpiperidin-1-yl)methyl]-N-[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-{[4-Cyano-4-(3,5-dibromopyridin-2-yl)piperidin-1-yl]methyl}-N-[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-[(4-Cyano-4-phenylpiperidin-1-yl)methyl]-N-[(3S,4S)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-{[4-(2-Bromophenyl)-4-cyanopiperidin-1-yl]methyl}-N-(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   rac-N-[(1R,2R)-2-Bromocyclohexyl)-1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizine-3-carboxamide; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-hydroxy-2-methylcyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-[(1R)-2-oxocyclohexyl]-4H-quinolizine-3-carboxamide; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylthio)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-{(1R,2R)-2-[(S)-methylsulfinyl]cyclohexyl}-4-oxo-4H-quinolizine-3-carboxamide; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylsulfonyl)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-3-yl-4H-quinolizine-3-carboxamide; -   Methyl     4-[({1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizin-3-yl}carbonyl)amino]piperidine-1-carboxylate; -   rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(3R,4S)-3-methyltetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-{[4-Cyano-4-(4-cyanopyridin-2-yl)piperidin-1-yl]methyl}-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-({4-Cyano-4-[4-(fluoromethyl)pyridine-2-yl}piperidin-1-yl]methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-({4-Cyano-4-[4-(difluoromethyl)pyridin-2-yl]piperidin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; -   1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-9-methyl-4-oxo-N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide;     and pharmaceutically acceptable salts thereof.

The invention is also directed to methods of treating a patient (preferably a human) for diseases or disorders in which the M1 receptor is involved, such as Alzheimer's Disease, cognitive impairment, schizophrenia, pain disorders and sleep disorders, by administering to the patient a therapeutically effective amount of a compound of formulas (I) to (III), or a pharmaceutically acceptable salt thereof.

The invention is also directed to the use of a compound of formulas (I) to (III), for treating a disease or disorder in which the M1 receptor is involved, such as Alzheimer's Disease, cognitive impairment, schizophrenia, pain disorders and sleep disorders, by administering to the patient a compound of formulas (I) to (III), or a pharmaceutically acceptable salt thereof.

The invention is also directed to medicaments or pharmaceutical compositions for the treatment of diseases or disorders in a patient (preferably a human) in which the M1 receptor is involved, such as Alzheimer's Disease, cognitive impairment, schizophrenia, pain disorders, and sleep disorders, which comprise a compound of formulas (I) to (III), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

The invention is also directed to a method for the manufacture of a medicament or a pharmaceutical composition for treating diseases in which M1 receptor is involved, such as Alzheimer's Disease, cognitive impairment, schizophrenia, pain disorders, and sleep disorders, comprising combining a compound of formulas (I) to (III), or a pharmaceutically acceptable salt thereof, with a pharmaceutically acceptable carrier.

Where a variable occurs more than once in any of formulas (I) to (III), or in a substituent thereof, the individual occurrences of that variable are independent of each other, unless otherwise specified.

As used herein, the term “alkyl,” by itself or as part of another substituent, means a saturated straight or branched chain hydrocarbon radical having the number of carbon atoms designated (e.g., C₁₋₁₀ alkyl means an alkyl group having from one to ten carbon atoms). Preferred alkyl groups for use in the invention are C₁₋₆ alkyl groups, having from one to six atoms. Exemplary alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-pentyl, hexyl, and the like. C₀ alkyl means a bond.

As used herein, the term “cycloalkyl,” by itself or as part of another substituent, means a saturated cyclic hydrocarbon radical having the number of carbon atoms designated (e.g., C₃₋₁₂ cycloalkyl means a cycloalkyl group having from three to twelve carbon atoms). The term cycloalkyl as used herein includes mono-, bi- and tricyclic saturated carbocycles, spirocycles, and bridged and fused ring carbocycles.

Preferred cycloalkyl groups for use in the invention are monocyclic C₃₋₈ cycloalkyl groups, having from three to eight carbon atoms. Exemplary monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like. Exemplary bridged cycloalkyl groups include adamantyl and norbornyl. Exemplary fused cycloalkyl groups include decahydronaphthalene.

As used herein, the term “heterocyclic,” by itself or as part of another substituent, means a cycloalkyl group as defined above, in which one or more of the ring carbon atoms is replaced with a heteroatom (such as N, S or O). Suitable non-aromatic heterocyclic groups for use in the invention include piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, tetrahydropyranyl, tetrahydrofuranyl and tetrahyropyrazopyrimidine. Preferred heterocyclic groups for use in the invention have four to eight ring atoms and a single nitrogen or oxygen heteroatom.

When a heterocyclic group as defined herein is substituted, the substituent may be bonded to a ring carbon atom of the heterocyclic group, or to a ring heteroatom (i.e., a nitrogen, oxygen or sulfur), which has a valence which permits substitution. Preferably, the substituent is bonded to a ring carbon atom. Similarly, when a heterocyclic group is defined as a substituent herein, the point of attachment may be at a ring carbon atom of the heterocyclic group, or on a ring heteroatom (i.e., a nitrogen, oxygen or sulfur), which has a valence which permits attachment. Preferably, the attachment is at a ring carbon atom.

As used herein, the term “alkenyl,” by itself or as part of another substituent, means a straight or branched chain hydrocarbon radical having a single carbon-carbon double bond and the number of carbon atoms designated (e.g., C₂₋₁₀ alkenyl means an alkenyl group having from two to ten carbon atoms). Preferred alkenyl groups for use in the invention are C₂₋₆ alkenyl groups, having from two to six carbon atoms. Exemplary alkenyl groups include ethenyl and propenyl.

As used herein, the term “aryl,” by itself or as part of another substituent, means an aromatic cyclic hydrocarbon radical. Preferred aryl groups have from six to ten carbons atoms. The term “aryl” includes multiple ring systems as well as single ring systems. Preferred aryl groups for use in the invention include phenyl and naphthyl.

The term “aryl” also includes fused cyclic hydrocarbon rings which are partially aromatic (i.e., one of the fused rings is aromatic and the other is non-aromatic). An exemplary aryl group which is partially aromatic is indanyl.

As used herein, the term “heteroaryl,” by itself or as part of another substituent, means a cyclic or polycyclic group having from five to twelve ring atoms selected from C, N, N→O, O and S, wherein at least one ring heteroatom is O, N, N→O or S, and wherein at least one of the constituent rings is aromatic. Exemplary heteroaryl groups for use in the invention include carbazolyl, carbolinlyl, chromenyl, cinnolinyl, furanyl, benzofuranyl, benzofurazanyl, isobenzofuranyl, imidazolyl, benzimidazolyl, benzimidazolonyl, indazolyl, indolyl, isoindolyl, indolinyl, indolazinyl, indynyl, oxadiazolyl, oxazolyl, benzoxazolyl, isoxazolyl, pyranyl, pyrazinyl, pyrazolyl, benzopyrazolyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl, quinolyl, isoquinolyl, tetrazolyl, thiazolyl, isothiazolyl, thiadiazolyl, thienyl, benzothioenyl, benzothiazolyl, quinoxalinyl, triazinyl and triazolyl, and N-oxides thereof.

One subgroup of heteroaryl groups have five ring atoms, the ring atoms selected from C, N, N→O or S, wherein one or two of the ring atoms is N, N→O or S. Exemplary heteroaryl groups in this embodiment are imidazolyl, pyrazolyl and thiazolyl.

Another subgroup of heteroaryl groups have six ring atoms, the ring atoms selected from C, N and N→O, wherein one or two of the ring atoms is N or N→O. Exemplary heteroaryl groups in this embodiment are pyridyl, pyridyl N-oxide and pyrimidinyl.

Another subgroup of heteroaryl groups have nine or ten ring atoms, the ring atoms selected from C, N, N→O and S, wherein one or two of the ring atoms is N, N→O or S.

The term “heteroaryl” also includes fused cyclic heterocyclic rings which are partially aromatic (i.e., one of the fused rings is aromatic and the other is non-aromatic). An exemplary heteroaryl group which is partially aromatic is benzodioxol.

When a heteroaryl group as defined herein is substituted, the substituent may be bonded to a ring carbon atom of the heteroaryl group, or on a ring heteroatom (i.e., a nitrogen, oxygen or sulfur), which has a valence which permits substitution. Preferably, the substituent is bonded to a ring carbon atom. Similarly, when a heteroaryl group is defined as a substituent herein, the point of attachment may be at a ring carbon atom of the heteroaryl group, or on a ring heteroatom (i.e., a nitrogen, oxygen or sulfur), which has a valence which permits attachment. Preferably, the attachment is at a ring carbon atom.

As used herein, the term “halo” or “halogen” includes fluoro, chloro, bromo and iodo.

The compounds of the invention may have one or more asymmetric centers. Compounds with asymmetric centers give rise to enantiomers (optical isomers), diastereomers (configurational isomers) or both, and it is intended that all of the possible enantiomers and diastereomers in mixtures and as pure or partially purified compounds are included within the scope of this invention. The present invention is meant to encompass all such isomeric forms of the compounds of formulas (I) to (III).

Formulas (I) or (II) are shown above without a definite stereochemistry. The present invention includes all stereoisomers of formulas (I) to (III), and pharmaceutically acceptable salts thereof.

The independent syntheses of the enantiomerically or diastereomerically enriched compounds, or their chromatographic separations, may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry may be determined by the x-ray crystallography of crystalline products or crystalline intermediates that are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.

If desired, racemic mixtures of the compounds may be separated so that the individual enantiomers or diastereomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diastereomeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods using chiral stationary phases, which methods are well known in the art.

Alternatively, any enantiomer or diastereomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art.

In the compounds of formulas (I) to (III), the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of generic formulas (I) to (III). For example, different isotopic forms of hydrogen (H) include protium (¹H) and deuterium (²H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Isotopically-enriched compounds within generic formulas (I) to (III) can be prepared without undue experimentation by conventional techniques well known to those skilled in the art or by processes analogous to those described in the Schemes and Examples herein using appropriate isotopically-enriched reagents and/or intermediates.

The term “substantially pure” means that the isolated material is at least 90% pure, and preferably 95% pure, and even more preferably 99% pure as assayed by analytical techniques known in the art.

As used herein, the term “muscarinic M1 receptor” refers to one of the five subtypes of the muscarinic acetylcholine receptor, which is from the superfamily of G-protein coupled receptors. The family of muscarinic receptors is described, for example, in Pharmacol Ther, 1993, 58:319-379; Eur J Pharmacol, 1996, 295:93-102, and Mol Pharmacol, 2002, 61:1297-1302. The muscarinic receptors are known to contain one or more allosteric sites, which may alter the affinity with which muscarinic ligands bind to the primary binding or orthosteric sites. See, e.g., S. Lazareno et al, Mol Pharmacol, 2002, 62:6, 1491-1505.

As used herein, the terms “positive allosteric modulator” and “allosteric potentiator” are used interchangeably, and refer to a ligand which interacts with an allosteric site of a receptor to activate the primary binding site. The compounds of the invention are positive allosteric modulators of the muscarinic M1 receptor. For example, a modulator or potentiator may directly or indirectly augment the response produced by the endogenous ligand (such as acetylcholine or xanomeline) at the orthosteric site of the muscarinic M1 receptor in an animal, in particular, a human.

The actions of ligands at allosteric receptor sites may also be understood according to the “allosteric ternary complex model,” as known by those skilled in the art. The allosteric ternary complex model is described with respect to the family of muscarinic receptors in Birdsall et al, Life Sciences, 2001, 68:2517-2524. For a general description of the role of allosteric binding sites, see Christopoulos, Nature Reviews: Drug Discovery, 2002, 1:198-210.

It is believed that the compounds of the invention bind to an allosteric binding site that is distinct from the orthosteric acetylcholine site of the muscarinic M1 receptor, thereby augmenting the response produced by the endogenous ligand acetylcholine at the orthosteric site of the M1 receptor. It is also believed that the compounds of the invention bind to an allosteric site which is distinct from the xanomeline site of the muscarinic M1 receptor, thereby augmenting the response produced by the endogenous ligand xanomeline at the orthosteric site of the M1 receptor.

The term “pharmaceutically acceptable salts” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. The compounds of the invention may be mono, di or tris salts, depending on the number of acid functionalities present in the free base form of the compound. Free bases and salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc, and the like.

Salts in the solid form may exist in more than one crystal structure, and may also be in the form of hydrates. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, and basic ion exchange resins, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylene-diamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like.

When the compound of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include acetic, trifluoroacetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, para-toluenesulfonic acid, and the like.

The present invention is directed to the use of the compounds of formulae (I) to (III) disclosed herein as M1 allosteric modulators in a patient or subject such as a mammal in need of such activity, comprising the administration of an effective amount of the compound. In addition to humans, a variety of other mammals can be treated according to the method of the present invention.

The compounds of the present invention have utility in treating or ameliorating Alzheimer's disease. The compounds may also be useful in treating or ameliorating other diseases mediated by the muscarinic M1 receptor, such as schizophrenia, sleep disorders, pain disorders (including acute pain, inflammatory pain and neuropathic pain) and cognitive disorders (including mild cognitive impairment). Other conditions that may be treated by the compounds of the invention include Parkinson's Disease, pulmonary hypertension, chronic obstructive pulmonary disease (COPD), asthma, urinary incontinence, glaucoma, schizophrenia, Trisomy 21 (Down Syndrome), cerebral amyloid angiopathy, degenerative dementia, Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch-Type (HCHWA-D), Creutzfeld-Jakob disease, prion disorders, amyotrophic lateral sclerosis, progressive supranuclear palsy, head trauma, stroke, pancreatitis, inclusion body myositis, other peripheral amyloidoses, diabetes, autism and atherosclerosis.

In preferred embodiments, the compounds of the invention are useful in treating Alzheimer's Disease, cognitive disorders, schizophrenia, pain disorders and sleep disorders.

For example, the compounds may be useful for the prevention of dementia of the Alzheimer's type, as well as for the treatment of early stage, intermediate stage or late stage dementia of the Alzheimer's type. In general, Alzheimer's Disease symptoms include confusion, irritability and aggression, mood swings, language breakdown, long-term memory loss, and the general withdrawal of the sufferer as their senses decline. The language problems associated with Alzheimer's Disease include a shrinking vocabulary and decreased word fluency. Alzheimer's Disease also includes impairment of fine motor tasks, such as writing, drawing, dressing and other coordinated movements. Alzheimer's Disease symptoms include apraxia (difficulties in movement planning).

Early stage Alzheimer's Disease is characterized by confusion, memory loss and changes in other cognitive abilities. Symptoms may include getting lost, trouble handling money and paying bills, repeating questions, taking longer to complete normal daily tasks, poor judgment, and mood and personality changes.

Intermediate stage Alzheimer's Disease is manifested by problems with reasoning, sensory processing, and conscious thought. Intermediate stage symptoms include continuing memory loss and confusion. Intermediate stage patients typically begin to have problems recognizing family and friends. Symptoms include the inability to learn new things, carry out tasks that involve multiple steps (such as getting dressed), or coping with new situations. Intermediate stage patients may have hallucinations, delusions, and paranoia, and may behave impulsively.

Patients suffering from severe Alzheimer's Disease are typically unable to communicate and are completely dependent on others for their care.

Potential schizophrenia conditions or disorders for which the compounds of the invention may be useful include one or more of the following conditions or diseases: schizophrenia or psychosis including schizophrenia (paranoid, disorganized, catatonic or undifferentiated), schizophreniform disorder, schizoaffective disorder, delusional disorder, brief psychotic disorder, shared psychotic disorder, psychotic disorder due to a general medical condition and substance-induced or drug-induced (phencyclidine, ketanine and other dissociative anaesthetics, amphetamine and other psychostimulants and cocaine) psychosispsychotic disorder, psychosis associated with affective disorders, brief reactive psychosis, schizoaffective psychosis, “schizophrenia-spectrum” disorders such as schizoid or schizotypal personality disorders, or illness associated with psychosis (such as major depression, manic depressive (bipolar) disorder, Alzheimer's disease and post-traumatic stress syndrome), including both the positive and the negative symptoms of schizophrenia and other psychoses; cognitive disorders including dementia (associated with Alzheimer's disease, ischemia, multi-infarct dementia, trauma, vascular problems or stroke, HIV disease, Parkinson's disease, Huntington's disease, Pick's disease, Creutzfeldt-Jacob disease, perinatal hypoxia, other general medical conditions or substance abuse); delirium, amnestic disorders or age related cognitive decline.

In another specific embodiment, the present invention provides a method for treating schizophrenia or psychosis comprising administering to a patient in need thereof an effective amount of a compound of the present invention. Particular schizophrenia or psychosis pathologies are paranoid, disorganized, catatonic or undifferentiated schizophrenia and substance-induced psychotic disorder. At present, the text revision of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) (2000, American Psychiatric Association, Washington D.C.) provides a diagnostic tool that includes paranoid, disorganized, catatonic or undifferentiated schizophrenia and substance-induced psychotic disorder. As used herein, the term “schizophrenia or psychosis” includes treatment of those mental disorders as described in DSM-IV-TR. The skilled artisan will recognize that there are alternative nomenclatures, nosologies and classification systems for mental disorders, and that these systems evolve with medical and scientific progress. Thus the term “schizophrenia or psychosis” is intended to include like disorders that are described in other diagnostic sources.

Examples of combinations of the compounds include combinations with agents for the treatment of schizophrenia, for example in combination with sedatives, hypnotics, anxiolytics, antipsychotics, antianxiety agents, cyclopyrrolones, imidazopyridines, pyrazolopyrimidines, minor tranquilizers, melatonin agonists and antagonists, melatonergic agents, benzodiazepines, barbiturates, 5HT-2 antagonists, and the like, such as: adinazolam, allobarbital, alonimid, aiprazolam, amisulpride, amitriptyline, amobarbital, amoxapine, aripiprazole, bentazepam, benzoctamine, brotizolam, bupropion, busprione, butabarbital, butalbital, capuride, carbocloral, chloral betaine, chloral hydrate, clomipramine, clonazepam, cloperidone, clorazepate, chlordiazepoxide, clorethate, chlorpromazine, clozapine, cyprazepam, desipramine, dexclamol, diazepam, dichloralphenazone, divalproex, diphenhydramine, doxepin, estazolam, ethchlorvynol, etomidate, fenobam, flunitrazepam, flupentixol, fluphenazine, flurazepam, fluvoxamine, fluoxetine, fosazepam, glutethimide, halazepam, haloperidol, hydroxyzine, imipramine, lithium, lorazepam, lormetazepam, maprotiline, mecloqualone, melatonin, mephobarbital, meprobamate, methaqualone, midaflur, midazolam, nefazodone, nisobamate, nitrazepam, nortriptyline, olanzapine, oxazepam, paraldehyde, paroxetine, pentobarbital, perlapine, perphenazine, phenelzine, phenobarbital, prazepam, promethazine, propofol, protriptyline, quazepam, quetiapine, reclazepam, risperidone, roletamide, secobarbital, sertraline, suproelone, temazepam, thioridazine, thiothixene, tracazolate, tranylcypromaine, trazodone, triazolam, trepipam, tricetamide, triclofos, trifluoperazine, trimetozine, trimipramine, uldazepam, venlafaxine, zaleplon, ziprasidone, zolazepam, zolpidem, and salts thereof, and combinations thereof, and the like, or the subject compound may be administered in conjunction with the use of physical methods such as with light therapy or electrical stimulation.

In another embodiment, the subject compound may be employed in combination with levodopa (with or without a selective extracerebral decarboxylase inhibitor such as carbidopa or benserazide), anticholinergics such as biperiden (optionally as its hydrochloride or lactate salt) and trihexyphenidyl (benzhexyl)hydrochloride, COMT inhibitors such as entacapone, MOA-B inhibitors, antioxidants, A2a adenosine receptor antagonists, cholinergic agonists, NMDA receptor antagonists, serotonin receptor antagonists and dopamine receptor agonists such as alentemol, bromocriptine, fenoldopam, lisuride, naxagolide, pergolide and pramipexole. It will be appreciated that the dopamine agonist may be in the form of a pharmaceutically acceptable salt, for example, alentemol hydrobromide, bromocriptine mesylate, fenoldopam mesylate, naxagolide hydrochloride and pergolide mesylate.

In another embodiment, the subject compound may be employed in combination with a compound from the phenothiazine, thioxanthene, heterocyclic dibenzazepine, butyrophenone, diphenylbutylpiperidine and indolone classes of neuroleptic agent. Suitable examples of phenothiazines include chlorpromazine, mesoridazine, thioridazine, acetophenazine, fluphenazine, perphenazine and trifluoperazine. Suitable examples of thioxanthenes include chlorprothixene and thiothixene. An example of a dibenzazepine is clozapine. An example of a butyrophenone is haloperidol. An example of a diphenylbutylpiperidine is pimozide. An example of an indolone is molindolone. Other neuroleptic agents include loxapine, sulpiride and risperidone. It will be appreciated that the neuroleptic agents when used in combination with the subject compound may be in the form of a pharmaceutically acceptable salt, for example, chlorpromazine hydrochloride, mesoridazine besylate, thioridazine hydrochloride, acetophenazine maleate, fluphenazine hydrochloride, flurphenazine enathate, fluphenazine decanoate, trifluoperazine hydrochloride, thiothixene hydrochloride, haloperidol decanoate, loxapine succinate and molindone hydrochloride. Perphenazine, chlorprothixene, clozapine, haloperidol, pimozide and risperidone are commonly used in a non-salt form. Thus, the subject compound may be employed in combination with acetophenazine, alentemol, aripiprazole, amisuipride, benzhexyl, bromocriptine, biperiden, chlorpromazine, chlorprothixene, clozapine, diazepam, fenoldopam, fluphenazine, haloperidol, levodopa, levodopa with benserazide, levodopa with carbidopa, lisuride, loxapine, mesoridazine, molindolone, naxagolide, olanzapine, pergolide, perphenazine, pimozide, pramipexole, quetiapine, risperidone, sulpiride, tetrabenazine, frihexyphenidyl, thioridazine, thiothixene, trifluoperazine or ziprasidone.

Potential sleep conditions or disorders for which the compounds of the invention may be useful include enhancing sleep quality; improving sleep quality; augmenting sleep maintenance; increasing the value which is calculated from the time that a subject sleeps divided by the time that a subject is attempting to sleep; decreasing sleep latency or onset (the time it takes to fall asleep); decreasing difficulties in falling asleep; increasing sleep continuity; decreasing the number of awakenings during sleep; decreasing nocturnal arousals; decreasing the time spent awake following the initial onset of sleep; increasing the total amount of sleep; reducing the fragmentation of sleep; altering the timing, frequency or duration of REM sleep bouts; altering the timing, frequency or duration of slow wave (i.e. stages 3 or 4) sleep bouts; increasing the amount and percentage of stage 2 sleep; promoting slow wave sleep; enhancing EEG-delta activity during sleep; increasing daytime alertness; reducing daytime drowsiness; treating or reducing excessive daytime sleepiness; insomnia; hypersomnia; narcolepsy; interrupted sleep; sleep apnea; wakefulness; nocturnal myoclonus; REM sleep interruptions; jet-lag; shift workers' sleep disturbances; dyssomnias; night terror; insomnias associated with depression, emotional/mood disorders, as well as sleep walking and enuresis, and sleep disorders which accompany aging; Alzheimer's sundowning; conditions associated with circadian rhythmicity as well as mental and physical disorders associated with travel across time zones and with rotating shift-work schedules; conditions due to drugs which cause reductions in REM sleep as a side effect; syndromes which are manifested by non-restorative sleep and muscle pain or sleep apnea which is associated with respiratory disturbances during sleep; and conditions which result from a diminished quality of sleep.

Pain disorders for which the compounds of the invention may be useful include neuropathic pain (such as postherpetic neuralgia, nerve injury, the “dynias”, e.g., vulvodynia, phantom limb pain, root avulsions, painful diabetic neuropathy, painful traumatic mononeuropathy, painful polyneuropathy); central pain syndromes (potentially caused by virtually any lesion at any level of the nervous system); postsurgical pain syndromes (eg, postmastectomy syndrome, postthoracotomy syndrome, stump pain); bone and joint pain (osteoarthritis), repetitive motion pain, dental pain, cancer pain, myofascial pain (muscular injury, fibromyalgia); perioperative pain (general surgery, gynecological), chronic pain, dysmennorhea, as well as pain associated with angina, and inflammatory pain of varied origins (e.g. osteoarthritis, rheumatoid arthritis, rheumatic disease, teno-synovitis and gout), headache, migraine and cluster headache, headache, primary hyperalgesia, secondary hyperalgesia, primary allodynia, secondary allodynia, or other pain caused by central sensitization.

Compounds of the invention may also be used to treat or prevent dyskinesias. Furthermore, compounds of the invention may be used to decrease tolerance and/or dependence to opioid treatment of pain, and for treatment of withdrawal syndrome of e.g., alcohol, opioids, and cocaine.

The subject or patient to whom the compounds of the present invention is administered is generally a human being, male or female, in whom M1 allosteric modulation is desired, but may also encompass other mammals, such as dogs, cats, mice, rats, cattle, horses, sheep, rabbits, monkeys, chimpanzees or other apes or primates, for which treatment of the above noted disorders is desired.

The compounds of the present invention may be used in combination with one or more other drugs in the treatment of diseases or conditions for which the compounds of the present invention have utility, where the combination of the drugs together are safer or more effective than either drug alone. Additionally, the compounds of the present invention may be used in combination with one or more other drugs that treat, prevent, control, ameliorate, or reduce the risk of side effects or toxicity of the compounds of the present invention. Such other drugs may be administered, by a route and in an amount commonly used therefor, contemporaneously or sequentially with the compounds of the present invention. Accordingly, the pharmaceutical compositions of the present invention include those that contain one or more other active ingredients, in addition to the compounds of the present invention. The combinations may be administered as part of a unit dosage form combination product, or as a kit or treatment protocol wherein one or more additional drugs are administered in separate dosage forms as part of a treatment regimen.

Examples of combinations of the compounds of the present invention include combinations with anti-Alzheimer's Disease agents, for example beta-secretase inhibitors; alpha 7 nicotinic agonists; ADAM 10 ligands or activators; gamma-secretase inhibitors; gamma secretase modulators; tau phosphorylation inhibitors; glycine transport inhibitors; LXR β agonists; ApoE4 conformational modulators; NR2B antagonists; androgen receptor modulators; blockers of Aβ oligomer formation; 5-HT4 agonists; 5-HT6 antagonists; 5-HT1a antagonists, such as lecozotan; p25/CDK5 inhibitors; NK1/NK3 receptor antagonists; COX-2 inhibitors; HMG-CoA reductase inhibitors; NSAIDs including ibuprofen; vitamin E; anti-amyloid antibodies (including anti-amyloid humanized monoclonal antibodies), such as bapineuzumab; anti-inflammatory compounds such as (R)-flurbiprofen, nitroflurbiprofen; PPAR gamma agonists, such as pioglitazone and rosiglitazone; CB-1 receptor antagonists or CB-1 receptor inverse agonists; antibiotics such as doxycycline and rifampin; N-methyl-D-aspartate (NMDA) receptor antagonists, such as memantine and neramexane; cholinesterase inhibitors such as galantamine, rivastigmine, donepezil, tacrine, phenserine and ladostigil; growth hormone secretagogues such as ibutamoren, ibutamoren mesylate, and capromorelin; histamine H₃ receptor antagonists; AMPA agonists or AMPA modulators; PDE IV inhibitors; PDE10A inhibitors; GABA_(A) inverse agonists; GSK3β inhibitors; neuronal nicotinic agonists; selective M1 agonists; HDAC inhibitors; and microtubule affinity regulating kinase (MARK) ligands; or other drugs that affect receptors or enzymes that either increase the efficacy, safety, convenience, or reduce unwanted side effects or toxicity of the compounds of the present invention.

Examples of combinations of the compounds include combinations with agents for the treatment of pain, for example non-steroidal anti-inflammatory agents, such as aspirin, diclofenac, duflunisal, fenoprofen, flurbiprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, naproxen, oxaprozin, piroxicam, sulindac and tolmetin; COX-2 inhibitors, such as celecoxib, rofecoxib and valdecoxib; CB-2 agonists; VR-1 antagonists; bradykinin B1 receptor antagonists; sodium channel blockers and antagonists; nitric oxide synthase (NOS) inhibitors (including iNOS and nNOS inhibitors); glycine site antagonists, including lacosamide; neuronal nicotinic agonists; NMDA antagonists; potassium channel openers; AMPA/kainate receptor antagonists; calcium channel blockers, such as ziconotide; GABA-A receptor IO modulators (e.g., a GABA-A receptor agonist); matrix metalloprotease (MMP) inhibitors; thrombolytic agents; opioid analgesics such as codeine, fentanyl, hydromorphone, levorphanol, meperidine, methadone, morphine, oxycodone, oxymorphone, pentazocine, propoxyphene; neutrophil inhibitory factor (NIP); pramipexole, ropinirole; anticholinergics; amantadine; monoamine oxidase B15 (“MAO-B”) inhibitors; 5HT receptor agonists or antagonists; mGlu5 antagonists; alpha agonists; neuronal nicotinic agonists; NMDA receptor agonists or antagonists; NKI antagonists; selective serotonin reuptake inhibitors (“SSRI”) and/or selective serotonin and norepinephrine reuptake inhibitors (“SSNRI”), such as duloxetine; tricyclic antidepressant drugs, norepinephrine modulators; lithium; valproate; gabapentin; pregabalin; rizatriptan; zolmitriptan; naratriptan and sumatriptan.

The compounds of the present invention may be administered in combination with compounds useful for enhancing sleep quality and preventing and treating sleep disorders and sleep disturbances, including e.g., sedatives, hypnotics, anxiolytics, antipsychotics, antianxiety agents, antihistamines, benzodiazepines, barbiturates, cyclopyrrolones, orexin antagonists, alpha-1 antagonists, GABA agonists, 5HT-2 antagonists including 5HT-2A antagonists and 5HT-2A/2C antagonists, histamine antagonists including histamine H3 antagonists, histamine H3 inverse agonists, imidazopyridines, minor tranquilizers, melatonin agonists and antagonists, melatonergic agents, other orexin antagonists, orexin agonists, prokineticin agonists and antagonists, pyrazolopyrimidines, T-type calcium channel antagonists, triazolopyridines, and the like, such as: adinazolam, allobarbital, alonimid, alprazolam, amitriptyline, amobarbital, amoxapine, armodafinil, APD-125, bentazepam, benzoctamine, brotizolam, bupropion, busprione, butabarbital, butalbital, capromorelin, capuride, carbocloral, chloral betaine, chloral hydrate, chlordiazepoxide, clomipramine, clonazepam, cloperidone, clorazepate, clorethate, clozapine, conazepam, cyprazepam, desipramine, dexclamol, diazepam, dichloralphenazone, divalproex, diphenhydramine, doxepin, EMD-281014, eplivanserin, estazolam, eszopiclone, ethchlorynol, etomidate, fenobam, flunitrazepam, flurazepam, fluvoxamine, fluoxetine, fosazepam, gaboxadol, glutethimide, halazepam, hydroxyzine, ibutamoren, imipramine, indiplon, lithium, lorazepam, lormetazepam, LY-156735, maprotiline, MDL-100907, mecloqualone, melatonin, mephobarbital, meprobamate, methaqualone, methyprylon, midaflur, midazolam, modafinil, nefazodone, NGD-2-73, nisobamate, nitrazepam, nortriptyline, oxazepam, paraldehyde, paroxetine, pentobarbital, perlapine, perphenazine, phenelzine, phenobarbital, prazepam, promethazine, propofol, protriptyline, quazepam, ramelteon, reclazepam, roletamide, secobarbital, sertraline, suproclone, TAK-375, temazepam, thioridazine, tiagabine, tracazolate, tranylcypromaine, trazodone, triazolam, trepipam, tricetamide, triclofos, trifluoperazine, trimetozine, trimipramine, uldazepam, venlafaxine, zaleplon, zolazepam, zopiclone, zolpidem, and salts thereof, and combinations thereof, and the like, or the compound of the present invention may be administered in conjunction with the use of physical methods such as with light therapy or electrical stimulation.

In another embodiment, the subject compound may be employed in combination with levodopa (with or without a selective extracerebral decarboxylase inhibitor such as carbidopa or benserazide), anticholinergics such as biperiden (optionally as its hydrochloride or lactate salt) and trihexyphenidyl (benzhexyl)hydrochloride, COMT inhibitors such as entacapone, MAO-B inhibitors, antioxidants, A2a adenosine receptor antagonists, cholinergic agonists and dopamine receptor agonists such as alentemol, bromocriptine, fenoldopam, lisuride, naxagolide, pergolide and pramipexole.

The term “composition” as used herein is intended to encompass a product comprising specified ingredients in predetermined amounts or proportions, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. This term in relation to pharmaceutical compositions is intended to encompass a product comprising one or more active ingredients, and an optional carrier comprising inert ingredients, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients.

In general, pharmaceutical compositions are prepared by uniformly and intimately bringing the active ingredient into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product into the desired formulation. In the pharmaceutical composition the active compound, which is a compound of formulae (I) to (VIII), is included in an amount sufficient to produce the desired effect upon the process or condition of diseases. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier.

The carrier may take a wide variety of forms depending on the form of preparation desired for administration, e.g., oral or parenteral (including intravenous). Thus, the pharmaceutical compositions of the present invention can be presented as discrete units suitable for oral administration such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient. Further, the compositions can be presented as a powder, as granules, as a solution, as a suspension in an aqueous liquid, as a non-aqueous liquid, as an oil-in-water emulsion or as a water-in-oil liquid emulsion. In addition to the common dosage forms set out above, the compounds of the invention, or pharmaceutically acceptable salts thereof, may also be administered by controlled release means and/or delivery devices.

Pharmaceutical compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets may contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be, for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period.

A tablet containing the composition of this invention may be prepared by compression or molding, optionally with one or more accessory ingredients or adjuvants. Compressed tablets may be prepared by compressing, in a suitable machine, the active ingredient in a free-flowing form such as powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active or dispersing agent. Molded tablets may be made by molding in a suitable machine, a mixture of the powdered compound moistened with an inert liquid diluent. Each tablet preferably contains from about 0.1 mg to about 500 mg of the active ingredient and each cachet or capsule preferably containing from about 0.1 mg to about 500 mg of the active ingredient.

Compositions for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Other pharmaceutical compositions include aqueous suspensions, which contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. In addition, oily suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. Oily suspensions may also contain various excipients. The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions, which may also contain excipients such as sweetening and flavoring agents.

The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleaginous suspension, or in the form of sterile powders for the extemporaneous preparation of such sterile injectable solutions or dispersions. In all cases, the final injectable form must be sterile and must be effectively fluid for easy syringability. The pharmaceutical compositions must be stable under the conditions of manufacture and storage; thus, preferably should be preserved against the contaminating action of microorganisms such as bacteria and fungi.

Pharmaceutical compositions of the present invention can be in a form suitable for topical use such as, for example, an aerosol, cream, ointment, lotion, dusting powder, or the like. Further, the compositions can be in a form suitable for use in transdermal devices. These formulations may be prepared via conventional processing methods. As an example, a cream or ointment is prepared by mixing hydrophilic material and water, together with about 5 wt % to about 10 wt % of the compound, to produce a cream or ointment having a desired consistency.

Pharmaceutical compositions of this invention can also be in a form suitable for rectal administration wherein the carrier is a solid. It is preferable that the mixture forms unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art.

By “pharmaceutically acceptable” it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The terms “administration of” or “administering a” compound should be understood to mean providing a compound of the invention to the individual in need of treatment in a form that can be introduced into that individual's body in a therapeutically useful form and therapeutically useful amount, including, but not limited to: oral dosage forms, such as tablets, capsules, syrups, suspensions, and the like; injectable dosage forms, such as IV, IM, or IP, and the like; transdermal dosage forms, including creams, jellies, powders, or patches; buccal dosage forms; inhalation powders, sprays, suspensions, and the like; and rectal suppositories.

The terms “effective amount” or “therapeutically effective amount” means the amount of the subject compound that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician.

As used herein, the term “treatment” or “treating” means any administration of a compound of the present invention and includes (1) inhibiting the disease in an animal that is experiencing or displaying the pathology or symptomatology of the diseased (i.e., arresting further development of the pathology and/or symptomatology), or (2) ameliorating the disease in an animal that is experiencing or displaying the pathology or symptomatology of the diseased (i.e., reversing the pathology and/or symptomatology).

The compositions containing compounds of the present invention may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pharmacy. The term “unit dosage form” is taken to mean a single dose wherein all active and inactive ingredients are combined in a suitable system, such that the patient or person administering the drug to the patient can open a single container or package with the entire dose contained therein, and does not have to mix any components together from two or more containers or packages. Typical examples of unit dosage forms are tablets or capsules for oral administration, single dose vials for injection, or suppositories for rectal administration. This list of unit dosage forms is not intended to be limiting in any way, but merely to represent typical examples of unit dosage forms.

The compositions containing compounds of the present invention may conveniently be presented as a kit, whereby two or more components, which may be active or inactive ingredients, carriers, diluents, and the like, are provided with instructions for preparation of the actual dosage form by the patient or person administering the drug to the patient. Such kits may be provided with all necessary materials and ingredients contained therein, or they may contain instructions for using or making materials or components that must be obtained independently by the patient or person administering the drug to the patient.

When treating or ameliorating a disorder or disease for which compounds of the present invention are indicated, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.1 mg to about 100 mg per kg of animal body weight, preferably given as a single daily dose or in divided doses two to six times a day, or in sustained release form. The total daily dosage is from about 1.0 mg to about 2000 mg, preferably from about 0.1 mg to about 20 mg per kg of body weight. In the case of a 70 kg adult human, the total daily dose will generally be from about 7 mg to about 1,400 mg. This dosage regimen may be adjusted to provide the optimal therapeutic response. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.

The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. For example, a formulation intended for the oral administration to humans may conveniently contain from about 0.005 mg to about 2.5 g of active agent, compounded with an appropriate and convenient amount of carrier material. Unit dosage forms will generally contain between from about 0.005 mg to about 1000 mg of the active ingredient, typically 0.005, 0.01 mg, 0.05 mg, 0.25 mg, 1 mg, 5 mg, 25 mg, 50 mg, 100 mg, 200 mg, 300 mg, 400 mg, 500 mg, 600 mg, 800 mg or 1000 mg, administered once, twice or three times a day.

It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

The compounds of the invention may be prepared according to the following reaction Schemes, in which variables are as defined before or are derived, using readily available starting materials, from reagents and conventional synthetic procedures. It is also possible to use variants, which are themselves known to those of ordinary skill in organic synthesis art, but are not mentioned in greater detail.

The present invention also provides a method for the synthesis of compounds useful as intermediates in the preparation of compounds of the invention.

The compounds of the invention may be prepared according to the following reaction Schemes, in which variables are as defined before or are derived, using readily available starting materials, from reagents and conventional synthetic procedures. It is also possible to use variants which are themselves known to those of ordinary skill in organic synthesis art, but are not mentioned in greater detail.

Compound 1 is described in the literature (J. Am. Chem. Soc.; 126; 50; 2004; 16353-16360) and can undergo reductive amination with an amine such as 2 using a reducing agent like sodium triacetoxyborohydride in an appropriate solvent. Hydrolysis of the ester group can be carried out using a base like sodium hydroxide in solvents such as THF, ethanol, or DMSO to afford carboxylic acid 3. Coupling of 3 with an amine using a coupling reagent such as BOP (benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate) in a solvent like DMF affords Example 1.

Amines such as 2 may be prepared as shown in Scheme 2. Bis-alkylation of the appropriate cyanomethyl derivative 5 with a suitably protected bis-(choroethyl)amine may be carried out using a base like sodium hydride in DMSO to afford product 6. Removal of the Boc protecting group can be done using an acid such as HCl in a solvent like ethyl acetate to afford compound 2.

Alternatively, as shown in Scheme 3, compounds such as 2 may be prepared via nucleophilic displacement of a halopyridine such as 8 with anion of 7 in a solvent like toluene or THF. The anion of compound 7 may be generated using a base like potassium hexamethyldisilazane or lithium diisopropylamide.

As shown in Scheme 4, an organolithium reagent from 9 may be prepared and undergo addition to aldehyde 1 as described in Scheme 1 to afford 10. Subsequent deoxygenation may be carried out using a reagent like triethylsilane with an acid such as trilfluoroacetic acid in a suitable solvent like dichloromethane to provide 11. Subsequent hydrolysis and amide formation may be carried out as described in Scheme 1 to afford Example 2.

An additional approach to compounds of Example 1 is shown in Scheme 5. The appropriate halo (chloro, bromo, or iodo) substituted compound such as Example 2 can undergo cross coupling using a transition metal such as palladium in the presence of a phosphine ligand in a solvent like DMSO with the appropriate organometallic reagent such as boronic acid 13 to provide Example 3. The organometallic reagent may be aromatic or alkyl, and the metal can be tin, boron, zinc, or magnesium.

The present invention also provides a method for the synthesis of compounds useful as intermediates in the preparation of compounds of the invention.

During any of the above synthetic sequences it may be necessary or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J. F. W. McOmie, Plenum Press, 1973, and T. W. Greene & P/G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 1999. The protecting groups may be removed at a convenient sequent stage using methods known from the art.

Several methods for preparing the compounds of this invention are illustrated in the schemes and examples herein. Starting materials are made according to procedures known in the art or as illustrated herein. The following examples are provided so that the invention might be more fully understood.

Example 1 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide

A mixture of tert-butyl 4-cyanopiperidine-1-carboxylate (220 mg, 1.05 mmol) and 2-fluoropyridine (0.094 mL, 1.10 mmol) was dissolved in 5.2 mL of THF. The reaction was purged with a stream of nitrogen and cooled to −78° C. To this reaction was added sodium bis(trimethylsilyl)amide (1.0 M in THF, 1.47 mL, 1.47 mmol), which was stirred for 1 h. The reaction was warmed to ambient temperature, stirred for 1 hour, and quenched with a saturated ammonium chloride solution. The mixture was extracted with dichloromethane (3×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, concentrated, and subjected to silica gel chromatography eluting with 0-20% ethyl acetate in hexanes to provide tert-butyl 4-cyano-4-pyridin-2-ylpiperidine-1-carboxylate.

The above carboxylate (3.11 g, 10.8 mmol) was dissolved in 54 mL of dry ethyl acetate and cooled to 0° C. Anhydrous HCl gas was then bubbled through the solution for 5 minutes. The reaction was warmed to ambient temperature and stirred for 2 h. The reaction mixture was taken up in dichloromethane (100 mL) and slowly neutralized with a saturated sodium bicarbonate solution. The mixture was partitioned between water and dichloromethane. The aqueous layer was extracted with dichloromethane (6×50 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated to yield 4-pyridin-2-ylpiperidine-4-carbonitrile.

In a 10-20 mL Emrys™ process vial, a mixture of the ethyl 1-formyl-4-oxo-4H-quinolizine-3-carboxylate (684 mg, 2.79 mmol), 4-pyridin-2-ylpiperidine-4-carbonitrile (627 mg, 3.35 mmol), glacial acetic acid (0.96 mL, 16.7 mmol) and 4.1 mL of dichloroethane was stirred vigorously. To the stirring mixture was added resin-bound MP-cyanoborohydride (2.74 g, 5.58 mmol). The mixture was heated via Emrys Optimizer™ microwave to 120° C. for 30 minutes. Filtration and solvent removal provided material, which was subjected to silica gel chromatography eluting with 55-75% ethyl acetate in hexanes to provide ethyl 4-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-1-oxo-1,8a-dihydronaphthalene-2-carboxylate.

The above carboxylate (705 mg, 1.69 mmol) was dissolved in a 2:1 THF:EtOH solution (8.4 mL), treated with 1 N NaOH (1.78 mL, 1.78 mmol), and warmed to 60° C. for 16 hours. The reaction was concentrated in vacuo and the crude material was subjected to purification via preparative reverse phase HPLC. The pure fractions concentrated in vacuo, and the residue was treated with 1 N NaOH (2.74 mL, 2.74 mmol). After 1 h, the reaction was concentrated in vacuo, and the residue was washed with cold water (5 mL) to provide 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizine-3-carboxylic acid that gave a proton NMR spectrum consistent with theory and a high resolution mass spectrum (ES+) m/z of 389.1626 calculated for M+H⁺ [C₂₂H₂₀N₄O₃: 389.1608].

To a solution of the above compound (0.200 g, 0.487 mmol) in 5 mL of DMF was added tetrahydro-2H-pyran-4-amine (0.059 g, 0.58 mmol), benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (0.302 g, 0.682 mmol), and triethylamine (0.15 mL, 1.1 mmol). After 30 min, the mixture was diluted with dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via reverse phase HPLC to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 472.2330 calculated for M+H⁺ [C₂₇H₃₀N₅O₃: 472.2343]: ¹H NMR (400 MHz, CDCl₃) 9.78 (d, J=7.5 Hz, 1H), 9.41 (d, J=7.2 Hz, 1H), 8.66 (s, 1H), 8.59 (d, J=3.9 Hz, 1H), 8.19 (d, J=8.9 Hz, 1H), 7.75-7.65 (m, 2H), 7.61 (d, J=8.0 Hz, 1H), 7.32-7.23 (m, 1H), 4.29-4.25 (m, 1H), 4.03-3.98 (m, 2H), 3.82 (s, 2H), 3.62-3.56 (m, 2H), 3.02-2.99 (m, 2H), 2.66-2.58 (m, 2H), 2.33-2.26 (m, 2H), 2.09-2.01 (m, 4H), 1.74-1.64 (m, 2H).

Example 2 1-[(5-Bromopyridin-2-yl)methyl]-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

To a solution of 2,5-dibromopyridine (2.00 g, 8.44 mmol) in 50 mL of toluene at −78° C. was added n-butyllithium (2.5 M in toluene, 4.05 mL, 10.1 mmol) dropwise. After 2 h, a solution of ethyl 1-formyl-4-oxo-4H-quinolizine-3-carboxylate (1.86 g, 7.60 mmoL) in 50 mL of dichloromethane was added dropwise. The mixture was warmed to rt, and after 1 h, treated with saturated aqueous ammonium chloride and concentrated in vacuo. The residue was redissolved in dichloromethane, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 30-100% ethyl acetate in hexanes to provide ethyl 1-[(5-bromopyridin-2-yl)(hydroxyl)methyl]-4-oxo-4H-quinolizine-3-carboxylate that gave a mass ion (ES+) of 404.7 (⁸¹Br) for [M+H]⁺.

To a solution of above compound (1.50 g, 3.72 mmol) in 20 mL of dichloromethane was added triethylsilane (0.865 g, 7.44 mmol) and trifluoroacetic acid (1.43 mL, 18.6 mmol). The mixture was heated to 50° C., and after 4 h, treated with water and extracted 3× with dichloromethane. The combined organic solutions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 50-100% ethyl acetate in hexanes to provide ethyl 1-[(5-bromopyridin-2-yl)methyl]-4-oxo-4H-quinolizine-3-carboxylate that gave a proton NMR spectra consistent with theory and a mass (ES+) of 386.8 (⁷⁹Br) for [M+H⁺].

To a solution of the above compound (0.460 g, 1.19 mmol) in 5 mL of THF was added aqueous sodium hydroxide (5 M, 0.48 mL, 2.4 mmol). The mixture was heated to 80° C., and after 2 h, cooled to rt, concentrated in vacuo, and azeotroped 3× with toluene to provide 1-[(5-bromopyridine-2-yl)methyl]-4-oxo-4H-quinolizine-3-carboxylic acid that gave a mass ion (ES+) of 360.8 (⁸¹Br) for [M+H]⁺.

To a solution of the above compound (0.188 g, 0.525 mmol) in 5 mL of DMF was added (1S,2S)-2-aminocyclohexanol (0.072 g, 0.63 mmol), benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (0.465 g, 1.05 mmol), and triethylamine (0.15 mL, 1.1 mmol). After 15 the mixture was diluted with dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was purified via silica gel chromatography, eluting with 0-100% methanol in dichloromethane to provide the title compound that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 457.8 (⁷⁹Br) for [M+H⁺]: ¹H NMR (400 MHz, CDCl₃) δ 9.44 (d, J=7.5 Hz, 1H), 8.56-8.53 (m, 2H), 8.05 (d, J=9.0 Hz, 1H), 7.90-7.84 (m, 1H), 7.82-7.80 (m, 1H), 7.47-7.43 (m, 1H), 7.28-7.25 (m, 1H), 4.43 (s, 2H), 3.84-3.80 (m, 1H), 3.79-3.68 (m, 1H), 3.55-3.39 (m, 2H), 2.13-1.98 (m, 2H), 1.93-1.85 (m, 1H), 1.79-1.73 (m, 2H), 1.42-1.38 (m, 2H).

Example 3 N-[(1S,2S)-2-Hydroxycyclohexyl]-{-[5-(1-methyl-1H-pyrazol-4-yl)pyridine-2-yl]methyl}-4-oxo-4H-quinolizine-3-carboxamide

To a solution of 1-[(5-bromopyridin-2-yl)methyl]-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide (Example 2, 0.045 g, 0.099 mmol) in 2 mL of THF under an atmosphere of nitrogen was added aqueous cesium carbonate (1 N, 0.20 mL, 0.20 mmol), 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.062 g, 0.30 mmol), and bis(tri-tert-butylphosphine)palladium(0) (5.0 mg, 0.010 mmol). The reaction was heated at 100° C. for 15 h, cooled to rt, and concentrated in vacuo. The resultant residue was subjected to purification via reverse phase HPLC to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 472.2330 calculated for M+H⁺ [C₂₇H₃₀N₅O₃: 472.2343]: ¹H NMR (400 MHz, CD₃OD) δ 9.50 (d, J=7.0 Hz, 1H), 8.83 (s, 1H), 8.53-8.50 (m, 1H), 8.35-8.30 (m, 1H), 8.16 (s, 1H), 8.06-7.97 (m, 2H), 7.88 (d, J=8.0 Hz, 1H), 7.56 (d, J=8.2 Hz, 1H), 7.52-7.48 (m, 1H), 4.62 (s, 2H), 3.95 (s, 3H), 3.86-3.81 (m, 1H), 3.55-3.48 (m, 1H), 3.21-3.12 (m, 1H), 2.13-2.10 (m, 1H), 2.03-1.87 (m, 1H), 1.79-1.73 (m, 2H), 1.40-1.24 (m, 3H).

Example 4 N-[(1S,2S)-2-Hydroxycyclohexyl]-4-oxo-1-{[5-(1H-pyrazol-1-yl)pyridine-2-yl]methyl}-4H-quinolizine-3-carboxamide

To a solution of 1-[(5-bromopyridin-2-yl)methyl]-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide (Example 2, 0.045 g, 0.099 mmol) and pyrazole (0.020 g, 0.30 mmol) in 2 mL of DMSO under an atmosphere of nitrogen was added aqueous cesium carbonate (1 M, 0.20 mL, 0.20 mmol), trans-N, N-dimethylcyclohexane-1,2-diamine (0.014 g, 0.10 mmol), and copper(I) iodide (0.014 g, 0.076 mmol). The mixture was heated at 120° C. for 15 h, cooled to rt, and subjected to purification via reverse phase HPLC to provide the title compound that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 444.0 for [M+H]⁺: ¹H NMR (400 MHz, CD₃OD) δ 9.46 (d, J=7.6 Hz, 1H), 8.93 (s, 1H), 8.58 (s, 1H), 8.28 (s, 1H), 8.17-8.08 (m, 2H), 7.85-7.82 (m, 1H), 7.75 (s, 1H), 7.49-7.44 (m, 2H), 6.56-6.55 (m, 1H), 4.53 (s, 2H), 3.86-3.82 (m, 1H), 3.74-3.70 (m, 1H), 2.13-2.02 (m, 2H), 1.89-1.73 (m, 13H), 1.43-1.33 (m, 3H).

Example 5 1-({4-[6-(Difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of 1-[6-(difluoromethyl)pyridin-3-yl]piperazine

To a solution of 5-bromo-pyridine-2-carbaldehyde (1.02 g, 5.48 mmol) in 25 mL of dichloromethane at 0° C. was added [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxofluor, 1.1 mL, 6.0 mmol) dropwise. After 2 h, additional [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxofluor, 0.55 mL, 3.0 mmol) was added. After 2 h, the mixture was washed with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via silica gel chromatography, eluting with 0-5% ethyl acetate in hexanes to provide 5-bromo-2-(difluoromethyl)pyridine that gave a proton NMR spectra consistent with theory and a mass (ES+) of 210.0 (⁸¹Br) for [M+H⁺].

To a solution of the above compound (0.796 g, 3.83 mmol) in 10 mL of toluene under an atmosphere of nitrogen was added tert-butyl piperazine-1-carboxylate (0.855 g, 4.59 mmol), sodium tert-butoxide (1.10 g, 11.5 mmol), (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP, 0.238 g, 0.383 mmol), and tris(dibenzylideneacetone)dipalladium (0) (0.350 g, 0.383 mmol). The mixture was heated to 80° C. in a sealed vial for 3 h, cooled to rt, and diluted with dichloromethane. The organic solution was washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via silica gel chromatography, eluting with 0-30% ethyl acetate in hexanes to provide tert-butyl 4-[6-(difluoromethyl)pyridine-3-yl]piperazine-1-carboxylate that gave a mass ion (ES+) of 314.1 for [M+H⁺].

A solution of the above compound (1.15 g, 3.67 mmol) in 15 mL of ethyl acetate was saturated with HCl_((g)). After 1 h, the reaction was concentrated in vacuo to provide 1-[6-(difluoromethyl)pyridine-3-yl]piperazine dihydrochloride that gave a mass (ES+) of 214.2 for [M+H⁺].

To a solution of ethyl 1-formyl-4-oxo-4H-quinolizine-3-carboxylate (see Example 1, 10.1 g, 41.0 mmol) in a mixture of 137 mL of THF and 68 mL of ethanol was added aqueous sodium hydroxide (1N, 43.1 mL, 43.1 mmol). After 4 h, the reaction was concentrated in vacuo to provide sodium 1-formyl-4-oxo-4H-quinolizine-3-carboxylate that gave a mass ion (ES+) of 218.1 for [M+H]⁺.

To a solution of the above compound (5.51 g, 23.0 mmol) in 23 mL of DMF was added (1S,2S)-2-aminocyclohexanol (2.92 g, 25.3 mmol), benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (12.2 g, 27.6 mmol), and triethylamine (3.21 mL, 23.0 mmol). After 30 min, the mixture was diluted with dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant yellow solid was collected via filtration and washed with dichloromethane to provide 1-formyl-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide that gave a mass ion (ES+) of 315.1 for [M+H⁺].

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting 1-[6-(difluoromethyl)pyridin-3-yl]piperazine for 4-pyridin-2-ylpiperidine-4-carbonitrile and substituting 1-formyl-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide for ethyl 1-formyl-4-oxo-4H-quinolizine-3-carboxylate. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 512.2476 calculated for M+H⁺ [C₂₇H₃₂F₂N₅O₃: 512.2468]: ¹H NMR (400 MHz, CDCl₃) δ 9.88 (d, J=6.6 Hz, 1H), 9.42 (d, J=7.3 Hz, 1H), 8.63 (s, 1H), 8.26-8.22 (m, 2H), 7.73-7.70 (m, 1H), 7.47 (d, J=8.6 Hz, 1H), 7.37-7.20 (m, 2H), 6.58 (t, J=55.9 Hz, 1H), 4.38 (br s, 1H), 3.92-3.89 (m, 1H), 3.78 (s, 2H), 3.56-3.49 (m, 1H), 3.25 (t, J=4.9 Hz, 4H), 2.66 (t, J=4.9 Hz, 4H), 2.17-2.05 (m, 2H), 1.78-1.76 (m, 2H), 1.63-1.26 (m, 4H).

Example 6 N-[(1S,2S)-2-Hydroxycyclohexyl]-1-{[4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazin-1-yl]methyl}-4-oxo-4H-quinolizine-3-carboxylate

Synthesis of 1-(1-methyl-1H-pyrazol-4-yl)piperazin-2-one

To a solution of tert-butyl 3-oxopiperazine-1-carboxylate (0.164 g, 0.819 mmol) in 3 mL of isopropanol under an atmosphere of nitrogen was added 1-methyl-4-iodo-M-pyrazole (0.204 g, 0.983 mmol), ethylene glycol (0.051 g, 0.82 mmol), copper iodide (0.031 g, 0.16 mmol), and potassium phosphate (0.695 g, 3.28 mmol). The reaction was heated to 100° C. for 8 h, cooled to rt, and concentrated in vacuo. The residue was redissolved in dichloromethane, washed with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 10-100% ethyl acetate in hexanes to provide tert-butyl 4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazine-1-carboxylate that gave a mass ion (ES+) of 281.1 for [M+H]⁺.

A solution of the above compound (0.058 g, 0.21 mmol) in 2 mL of ethyl acetate at 0° C. was saturated with hydrogen chloride gas, then warmed to rt. After 18 h, the reaction was concentrated in vacuo, neutralized with saturated aqueous sodium bicarbonate, washed 3× with a 10% solution of methanol in dichloromethane, filtered, and concentrated in vacuo to provide 1-(1-methyl-1H-pyrazol-4-yl)piperazin-2-one that gave a mass ion (ES+) of 181.2 for [M+H]⁺.

The title compound was prepared by the procedure described for the synthesis of 1-({4-[6-(difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide in Example 5, substituting 1-(1-methyl-1H-pyrazol-4-yl)piperazin-2-one for 1-[6-(difluoromethyl)pyridin-3-yl]piperazine for 4-pyridin-2-ylpiperidine-4-carbonitrile. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 479.2416 calculated for M+H⁺ [C₂₅H₃₁N₆O₄: 479.2401]: ¹H NMR (400 MHz, CDCl₃) δ 9.83 (d, J=6.7 Hz, 1H), 9.43 (d, J=7.2 Hz, 1H), 8.63 (s, 1H), 8.16 (d, J=8.9 Hz, 1H), 8.00 (s, 1H), 7.74-7.69 (m, 1H), 7.43 (s, 1H), 7.36-7.32 (m, 1H), 4.32 (br s, 1H), 3.92-3.85 (m, 1H), 3.87 (s, 3H), 3.81 (s, 2H), 3.61-3.55 (m, 2H), 3.54-3.50 (m, 1H), 3.38-3.33 (m, 2H), 2.85-2.78 (m, 2H), 2.14-2.01 (m, 2H), 1.78-1.76 (m, 2H), 1.67-1.25 (m, 4H).

Example 7 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1yl)methyl]-N-[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide

Example 8 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1yl)methyl]-N-[(3R,4R)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of rac-(3R,4S)-4-aminotetrahydro-2H-pyran-3-ol and rac-(3R,4S)-3-aminotetrahydro-2H-pyran-4-ol

To a solution of tetrahydro-2H-pyran-4-ol (39.0 g, 0.382 mol) and triethylamine (692 mL, 0.496 mol) in 300 mL of chloroform at 0° C. was added methanesulfonylchloride (29.8 mL, 0.382 mol). After 1 h, water (100 mL) was added, and the mixture was extracted with chloroform (100 mL). The combined organic fractions were washed with brine, dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue was dissolved in 1,8-diazabicyclo[5.4.0]undec-7-ene (70 mL) with mild heating, then heated to 90 to 150° C. over 1 h. Four fractions were collected via distillation at ˜75° C. to provide 3,6-dihydro-2H-pyran.

To a solution of m-chloroperbenzoic acid (12.9 g, 74.9 mmol) in 70 mL of dichloromethane was added a solution of the above compound in 50 mL of dichloromethane. After 6 h, the mixture was washed 3× with 5% aqueous potassium carbonate, 1× with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to provide 3,7-dioxabicyclo[4.1.0]heptane that gave proton NMR spectra consistent with theory.

To a solution of the above compound (4.00 g, 40.0 mmol) in a mixture of 150 mL of methanol and 20 mL of water was added ammonium chloride (4.00 g, 74.8 mmol) and sodium azide (13.0 g, 200 mol). The reaction was heated to 75° C. for 15 h, then cooled to rt and concentrated in vacuo to ˜50 mL. The solution was diluted with water and extracted 3× with diethyl ether and the combined organic fractions were washed with saturated aqueous sodium bicarbonate and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. To a solution of this crude intermediate in 50 mL of methanol was added palladium on carbon (10%, 0.45 g, 0.42 mmol). The mixture was placed under an atmosphere of hydrogen (1 atm) for 48 h and was then filtered through a pad of Celite, which was washed with MeOH. The filtrate was concentrated in vacuo to provide a crude 5:1 mixture of rac-(3R,4S)-4-aminotetrahydro-2H-pyran-3-ol and rac-(3R,4S)-3-aminotetrahydro-2H-pyran-4-ol that gave a proton NMR spectra consistent with theory.

The title compounds 7 and 8 were prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting the crude mixture of rac-(3R,4S)-4-aminotetrahydro-2H-pyran-3-ol and rac-(3R,4S)-3-aminotetrahydro-2H-pyran-4-ol for tetrahydro-2H-pyran-4-amine. The crude products were subjected to purification via silica gel chromatography, eluting with 0-3% methanol in dichloromethane to provide the title compounds G and H.

Example 7 gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 488.2300 calculated for M+H⁺ [C₂₇H₃₀N₆O₄: 488.2292]: ¹H NMR (400 MHz, CDCl₃) δ 9.98 (d, J=5.7 Hz, 1H), 9.37 (d, J=6.9 Hz, 1H), 8.59 (s, 1H), 8.55-8.54 (m, 1H), 8.18 (d, J=8.7 Hz, 1H), 7.71-7.67 (m, 2H), 7.57 (d, J=8.0 Hz, 1H), 7.30-7.28 (m, 1H), 7.22-7.19 (m, 1H), 5.10 (br s, 1H), 4.07-4.02 (m, 1H), 4.01-3.92 (m, 2H), 3.77 (s, 2H), 3.63-3.57 (m, 1H), 3.46-3.40 (m, 1H), 3.22-3.16 (m, 1H), 2.97-2.94 (m, 2H), 2.56 (t, J=12.1 Hz, 2H), 2.29-2.21 (m, 2H), 2.05-1.98 (m, 3H), 1.85-1.79 (m, 1H).

Example 8 gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 488.2303 calculated for M+H⁺ [C₂₇H₃₀N₆O₄: 488.2292]: ¹H NMR (400 MHz, CDCl₃) δ 9.90 (d, J=6.8 Hz, 1H), 9.37 (d, J=7.2 Hz, 1H), 8.60 (s, 1H), 8.55 (d, J=4.3 Hz, 1H), 8.17 (d, J=8.9 Hz, 1H), 731-7.66 (m, 2H), 7.57 (d, J=8.0 Hz, 1H), 7.29-7.27 (m, 1H), 7.22-7.19 (m, 1H), 4.13-4.04 (m, 2H), 4.04-3.93 (m, 2H), 3.77 (s, 2H), 3.48-3.42 (m, 1H), 3.37-3.32 (m, 1H), 2.97-2.76 (m, 2H), 2.29-2.21 (m, 2H), 2.08-2.01 (m, 3H), 1.85-1.70 (m, 4H).

Example 9 1-[(4-Cyano-4-phenylpiperidin-1-yl)methyl]-N-[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol

To a crude 5:1 mixture of rac-(3R,4S)-4-aminotetrahydro-2H-pyran-3-ol and rac-(3R,4S)-3-aminotetrahydro-2H-pyran-4-ol (see Example 8, 3.50 g, 29.9 mmol) in 150 mL of water at 0° C. was added sodium carbonate (3.80 g, 35.9 mmol) followed by benzyl chloroformate (5.12 mL, 35.9 mmol) dropwise. After 30 min, the mixture was warmed to rt, and after 4 h, a solid precipitate was collected via filtration and recrystallized from ethyl acetate/hexanes to provide benzyl[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate that gave a proton NMR spectra consistent with theory. The filtrate was concentrated and the resultant residue was subjected to purification via silica gel chromatography, eluting with 30-70% ethyl acetate in hexanes to provide a mixture of benzyl[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate and benzyl [(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate. The two enantiomers were separated via chiral chromatography to provide pure benzyl[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate and benzyl[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate. The semi-preparative separation was performed on a 5 cm id by 50 cm length, 20 μm, AD column run at 85 mL/min in a mixture of 60% ethanol/40% heptane with 0.1% DEA added to both components.

To a solution of benzyl[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]carbamate (0.200 g, 0.796 mmol) in 8 mL of methanol saturated with HCl_((g)) at 0° C. was added palladium on carbon (10%, 0.10 g, 0.094 mmol). The mixture was placed under an atmosphere of hydrogen (1 atm) for 16 h and was then filtered through a pad of Celite, which was washed with MeOH. The filtrate was concentrated in vacuo to provide (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol that gave a proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting 4-phenylpiperidine-4-carbonitrile for 4-pyridin-2-ylpiperidine-4-carbonitrile and substituting (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol for tetrahydro-2H-pyran-4-amine. The resultant solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 487.2349 calculated for M+H⁺ [C₂₈H₃₁N₄O₄: 487.2340]: ¹H-NMR (400 MHz, CDCl₃) δ 9.98 (d, J=5.7 Hz, 1H), 9.38 (d, J=7.1 Hz, 1H), 8.61 (s, 1H), 8.13 (d, J=8.9 Hz, 1H), 7.71-7.66 (m, 1H), 7.44-7.41 (m, 2H), 7.37-7.26 (m, 4H), 5.09 (br s, 1H), 4.06-3.93 (m, 3H), 3.81 (s, 2H), 3.74-3.57 (m, 1H), 3.47-3.40 (m, 1H), 3.22-3.16 (m, 1H), 2.98-2.94 (m, 2H), 2.61-2.55 (m, 2H), 2.09-1.96 (m, 5H), 1.86-1.76 (m, 1H).

Example 10 1-{[4-Cyano-4-(3,5-dibromopyridin-2-yl)piperidin-1-yl]methyl}-N-[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of (3R,4S)-4-Aminotetrahydro-2H-pyran-3-ol

A jacketed flask equipped with an overhead stirrer and a thermocouple was charged with 23.0 L of MeOH, and cooled to 5° C. Potassium hydroxide (1.574 kg, 28.05 mol) was added to the flask, and the resulting solution was aged until homogeneous and recooled to 5° C. Tetrahydro-4H-pyran-4-one (1.00 kg, 10.0 mol) was then added at a steady rate over 20 min, and the resulting solution was aged for 20-30 min. A solution of iodine (2.778 kg, 10.95 mol) in 18.5 L of MeOH was then added via mechanical pump at a steady rate over 90-100 minutes. After an additional 30 min, the solution was warmed to rt and toluene (42.0 L) was added. The resulting slurry was concentrated in vacuo to a volume of ˜8.4 L. Additional toluene (8.4 L) was added and the resulting solution was concentrated to a volume of 8.4 L 2×. The resulting slurry was then filtered, and the filter cake was rinsed 2× with toluene (4.0 L). The combined toluene streams were concentrated to ˜6 L, and the product is extracted 2× with water (3.0 L) to provide 4,4-dimethyoxytetrahydro-2H-pyran-3-ol.

To a solution of the above compound (1.00 kg, 6.17 mol) in 5 L of water was added acetic acid to pH 5.2-5.4. The mixture was diluted with acetonitrile (4.0 L) and ruthenium trichloride hydrate (6.4 g, 0.028 mol) was added and rinsed in with additional acetonitrile (1.0 L). The flask was placed in a rt water bath and a solution of sodium bromate (650 g, 4.31 mol) in water (1.95 L) was added slowly over ˜30 min, keeping the temperature below 30° C. After 2 h, potassium bicarbonate (430 g, 4.30 mol), sodium thiosulfate (1.07 kg, 4.31 mol), potassium chloride (500 g, 6.71 mol) and acetonitrile (5 L) were added sequentially. The layers were separated and the aqueous layer was extracted 3× with acetonitrile (10 L). The combined organic extracts were concentrated to ˜4 L. Toluene (5 L) was then added and the mixture reconcentrated to 4 L 4×. The mixture was diluted with toluene (7 L) and filtered to remove solids. The filter cake was washed 3× with toluene (2 L) and the combined filtrate and washes were concentrated to a total volume of 3 L to provide an organic solution of 4,4-dimethoxydihydro-2H-pyran-3(4H)-one.

To a 3 L 3-neck RB flask with overhead stirring, thermocouple and heating mantle was added sodium dihydrogenphosphate (96.0 g, 800 mmol) in 1.6 L of water. Sodium hydroxide (29 mL, 50 wt %) was added to pH 7.13, followed by hydrochloric acid (5 mL, 6 N) to pH 7.02.

The above organic solution of 4,4-dimethoxydihydro-2H-pyran-3(4H)-one was extracted 3× with phosphate buffered water (0.55 L). To the combined aqueous extracts was added D-glucose (180 g, 100 mmol), and the solution was heated to 30° C. When the solution exceeded 27° C. upon heating B-NADP+ (1.60 g, 499 mmol) GDH-103 (1.60 g, 499 mmol) and KRED-130 (1.60 g, 499 mmol) were added and the mixture was stirred for 17 h at 30° C. Potassium chloride (200 g, 2.68 mol) and acetonitrile (1.3 L) were added. After 30 min, the reaction mixture was transferred to 6 L sep funnel and additional MeCN (0.67 L) and toluene (0.87 L) were added. The aqueous layer was back extracted 1× with a mixture of acetonitrile (1.95 L) and toluene (0.65 L), and 1× with acetonitrile (1.5 L). The combined organic extracts were concentrated in vacuo to provide (3S)-4,4-dimethoxytetrahydro-2H-pyran-3-ol.

To a 2 L RB flask with overhead stirring, thermocouple, heating mantle and N₂ inlet was added a solution of the above compound (72.0 g, 0.444 mol) in 750 mL of THF. After 15 h, sodium ten-butoxide (48.3 g, 492 mmol) was added in one portion, and the mixture was heated to 35° C. for 1 h, and aged at 22° C. for 1 hr. Tetrabutylammonium iodide (8.19 g, 22.2 mmol) and benzyl bromide (56.5 ml, 466 mmol) were added, and the mixture was heated to 50° C. for 2 h. The solution was cooled to 25° C., and water (750 mL) and MtBE (2.25 L) were added. The organic layer was separated from the aqueous and concentrated in vacuo. The resultant brown oil was purified via silica gel chromatography, eluting with 0-15% ethyl acetate in hexanes to provide (3S)-3-(benzylyoxy)-4,4-dimethoxytetrahydro-2H-pyran.

To a solution of the above compound (61.1 g, 225 mmol) in 300 mL of THF was added 2 N HCl (300 mL, 0.600 mol). After 1.5 h, saturated aqueous potassium carbonate (60 mL) was added via addition funnel to pH 7.4. The aqueous layer was extracted 3× with MtBE (300 mL) and the combined organic extracts were concentrated in vacuo to provide crude (3S)-3-(benzyloxy)tetrahydro-4H-pyran-4-one.

To a solution of L-Alanine (200 g, 2.24 mol), sodium formate (76.0 g, 1.12 mmol), and sodium phosphate dibasic (28.7 g, 202 mmol) in 2.25 L of water adjusted to pH 7.5 was added NAD (2.2 g, 3.21 mmol), pyridoxal-5-phosphate (2.2 g, 8.90 mmol), LDH (0.45 g, 0.22 mol), FDH (4.5 g, 0.20 mol), and TA P1G5 (4.5 g, 0.22 mol) [CDX TA P1G5=Codex Transaminase panel enzyme P1G5, which is commercially available from Codexis (Redwood City, Calif., USA)]. After all the components were completely dissolved, (3S)-3-(benzyloxy)tetrahydro-4H-pyran-4-one (45 g, 0.22 mol) was added and the pH was adjusted to pH 7.25 with 6 N HCl and aged at 30° C. After 15 h, potassium carbonate (700 g, 5.06 mol) was added slowly, followed by ethyl acetate (2.2 L). The mixture was filtered through a bed of Solka Floc and the cake was washed with ethyl acetate (250 mL). The combined filtrates were separated and the aqueous layer was extracted a second time with ethyl acetate (2 L). The combined organic extracts were concentrated in vacuo to provide crude (3R,4S)-3-(benzyloxy)tetrahydro-2H-pyran-4-amine.

To a solution of the above compound (38.8 g, 0.187 mol) in 730 mL of methanol was added concentrated hydrochloric acid (23.3 mL). The solution was subjected to hydrogenation at 40 psi H₂, 25° C. over 5.8 g of 10% Pd/C (5.8 g). After 15 h, the mixture was filtered through solka floc and the filtercake was washed 5× with methanol (100 mL). The combined filtrate and washes were concentrated in vacuo to provide (3R,4S)-4-aminotetrahydro-2H-pyran-3-ol that gave proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting 3,5-dibromo-2-fluoropyridine for 2-fluoropyridine and substituting (3R,4S)-4-aminotetrahydro-2H-pyran-3-ol for tetrahydro-2H-pyran-4-amine. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 644.0524 calculated for M+H⁺ [C₂₇H₂₈Br₂N₅O₄: 644.0503]: ¹H NMR (400 MHz, CDCl₃) δ 10.01 (d, J=5.6 Hz, 1H), 9.42 (d, J=7.0 Hz, 1H), 8.66-8.64 (m, 2H), 8.18 (d, J=8.6 Hz, 1H), 7.87 (s, 1H), 7.72 (d, J=8.4 Hz, 1H), 7.31 (d, J=6.1 Hz, 1H), 4.11-4.05 (m, 1H), 4.02-3.85 (m, 1H), 3.81 (s, 2H), 3.65 (br s, 1H), 3.48-3.45 (m, 1H), 3.26-3.21 (m, 1H), 3.02-2.98 (m, 1H), 2.61-2.50 (m, 2H), 2.27-2.20 (m, 2H), 2.07-1.87 (m, 3H), 1.85-1.75 (m, 1H).

Example 11 1-[(4-Cyano-4-phenylpiperidin-1-yl)methyl]-N-[(3S,4S)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of (3S,4S)-3-aminotetrahydro-2H-pyran-4-ol

A solution of 4,4-dimethoxydihydro-2H-pyran-3(4H)-one (172 g, 1.07 mol, see Example 1) in 310 mL of toluene was stirred in toluene for 30 min, then extracted 3× with water (270 mL). To the aqueous solution was added potassium dihydrogenphosphate (14.1 g, 0.104 mol), sodium formate (55.1 g, 0.810 mol), and L-Alanine (72.2 g, 0.810 mol). The pH was adjusted to 7.8 with 5 N NaOH, and NAD (0.810 g), PLP (0.810 g), LDH (0.162 g), FDH (1.62 g), and Codexis TA P1G5 (4.05 g) were added. The mixture was heated to 45° C. for 12 h, then cooled to rt. Potassium carbonate (324 g, 2.34 mol) was added, and after 30 min, the mixture was diluted with acetonitrile (810 mL). After 30 min, the reaction was filtered through a pad of solka-floc. The filtrate was partitioned and the aqueous layer was extracted with additional acetonitrile (810 mL). The combined organic fractions were concentrated in vacuo to provide crude (3S)-4,4-dimethoxytetrahydro-2H-pyran-3-amine.

The above residue was redissolved in 700 mL of THF and 254 mL of water, and cooled to 0° C. Sodium hydroxide (5 N, 96 mL, 0.48 mol) was added, and the reaction was recooled to −5° C. Benzyl chloroformate (68.0 mL, 0.476 mol) was added via a syringe pump over 30 min, and the mixture was then warmed to rt. HCl (6 N, 250 mL, 1.50 mol) was added to pH=0.40, and the mixture was stirred with an overhead stirrer. After 2 h, 3 M potassium carbonate was added to pH=7.4, and the reaction was diluted with THF (700 mL). A white solid was removed via filtration, and washed with additional THF (100 mL). The combined organic fractions were concentrated in vacuo to provide crude benzyl[(3S)-4-oxotetrahydro-2H-pyran-3-yl]carbamate.

To a solution of potassium dihydrogen phosphate (62.7 g, 0.461 mol) in 13.6 L of water was added phosphoric acid to pH=7.0. To this solution was added glucose (112 g, 0.622 mol), NADP (3.6 g), GDH-103 (1.8 g), KRED 119 (3.6 g), and crude benzyl[(3S)-4-oxotetrahydro-2H-1-pyran-3-yl]carbamate (103.4 g, 0.4148 mol). After 17 h, the reaction was adjusted to pH=6.5 with 5 N NaOH. A white solid was collected via filtration and washed 2× with water (200 mL). The solid was suspended in 600 mL of toluene and stirred with an overhead stirrer at 105° C. for 1 h, then cooled to rt. A white solid was collected via filtration and washed with toluene (200 mL) to provide benzyl[(3S,4S)-4-hydroxytetrahydro-2H-pyran-3-yl]carbamate.

To a solution of the above compound (90.5 g, 0.360 mol) in 1.8 L of methanol was added palladium hydroxide on carbon (9 g). The mixture was subjected to 40 psi of hydrogen at 25° C. for 15 h, then filtered through solka-floc. The filter cake was washed 3× with methanol (200 mL), and the combined filtrates were concentrated in vacuo to provide crude (3S,4S)-3-aminotetrahydro-2H-pyran-4-ol that gave proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting 4-phenylpiperidine-4-carbonitrile for 4-pyridin-2-ylpiperidine-4-carbonitrile and substituting (3S,4S)-3-aminotetrahydro-2H-pyran-4-ol for tetrahydro-2H-pyran-4-amine. The resultant yellow solid gave a mass ion (ES+) of 487.2 for [M+H]⁺.

Example 12 1-{[4-(2-Bromophenyl)-4-cyanopiperidin-1-yl]methyl}-N-(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of 4-(2-bromophenyl)piperidine-4-carbonitrile

To a solution of bis(2-chloroethyl)amine hydrochloride (5.00 g, 28.0 mmol) in 140 mL of THF was added triethylamine (4.10 mL, 29.4 mmol) and di-tert-butyl dicarbonate (6.42 g, 29.4 mmol). After 2 h, the reaction was diluted with dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via silica gel chromatography, eluting with 0-10% ethyl acetate in hexanes to provide tert-butyl bis(2-chloroethyl) carbamate that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (2.04 g, 8.40 mmol) and 2-bromophenylacetonitrile (1.648 g, 8.40 mmol) in 20 mL of DMSO at 18° C. was added sodium hydride (0.739 g, 18.5 mmol). The mixture was warmed to rt, and after 30 min, heated to 50° C. After 5 h, the reaction was diluted with dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via silica gel chromatography, eluting with 0-20% ethyl acetate in hexanes to provide tert-butyl 4-(2-bromophenyl)-4-cyanopiperidine-1-carboxylate that gave a mass ion (ES+) of 367.0 (⁸¹Br) for [M+H⁺].

A solution of the above compound (0.072 g, 0.20 mmol) in 2 mL of ethyl acetate was saturated with HCl_((g)). After 1 h, the reaction was concentrated in vacuo to provide 4-(2-bromophenyl)piperidine-4-carbonitrile hydrochloride that gave a mass ion (ES+) of 265.0 (⁷⁹Br) for [M+H⁺].

The title compound was prepared by the procedure described for the synthesis of 1-({4-[6-(difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide in Example 5, substituting 4-(2-bromophenyl)piperidine-4-carbonitrile for 1-[6-(difluoromethyl)pyridin-3-yl]piperazine for 4-pyridin-2-ylpiperidine-4-carbonitrile. The resultant solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 563.1666 calculated for M+H⁺ [C₂₉H₃₂BrN₄O₃: 563.1652]: ¹H NMR (400 MHz, CDCl₃) δ 9.87 (d, J=6.6 Hz, 1H), 9.41 (d, J=7.1 Hz, 1H), 8.69 (s, 1H), 8.14 (d, J=8.8 Hz, 1H), 7.69-6.77 (m, 2H), 7.38-7.18 (m, 4H), 4.35 (br s, 1H), 3.90-3.85 (m, 1H), 3.83 (s, 2H), 3.54-3.49 (m, 1H), 3.03-3.00 (m, 2H), 2.74-2.68 (m, 2H), 2.59-2.56 (m, 2H), 2.12-2.08 (m, 3H), 1.78-1.75 (m, 2H), 1.61-1.27 (m, 4H).

Example 13 rac-N-[(1R,2R)-2-Bromocyclohexyl)-1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of rac-(1R,2R)-2-bromocyclohexanamine

A solution of cyclohexene oxide (10.1 g, 103 mmol) and sodium azide (16.7 g, 257 mmol) in 100 mL of a 1:1 mixture of acetone:water was heated to reflux at 75° C. for 14 h. The mixture was cooled to rt, concentrated in vacuo to 50 mL, and extracted 3× with dichloromethane. The combined organic fractions were washed 2× with water, dried over sodium sulfate, filtered, and concentrated in vacuo to provide 2-azidocyclohexanol that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (14.9 g, 105 mmol) in 100 mL of MTBE was added triphenylphosphine. The mixture was heated to reflux for 18 h, cooled to rt, filtered through a Buchner funnel, and concentrated in vacuo to provide 7-azabicyclo[4.1.0]heptane that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (10.2 g, 105 mmol) in 350 mL of dichloromethane at 0° C. was added triethylamine (17.6 mL, 126 mmol) followed by benzyl chloroformate (18.0 mL, 126 mmol) dropwise. After 3 h, the reaction was washed with saturated aqueous sodium bicarbonate and brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-10% ethyl acetate in hexanes to provide benzyl 7-azabicyclo[4.1.0]heptane-7-carboxylate that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (0.314 g, 1.36 mmoL) in 7 mL of THF at −40° C. was added methylmagnesium bromide (3 M in diethyl ether, 0.50 mL, 1.5 mmol) dropwise. After 1 h, the reaction was warmed to rt and after 18 h, treated with water and extracted 3× with dichloromethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-25% ethyl acetate in hexanes to provide benzyl rac-[(1R,2R)-2-bromocyclohexyl]carbamate that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 314.0 (⁸¹Br) for [M+H]⁺.

To a solution of the above compound (0.075 g, 0.24 mmoL) in 1 mL of dichloromethane at 0° C. was added boron tribromide (1 M in dichloromethane, 0.26 mL, 0.26 mmol) dropwise. After 1 h, the mixture was warmed to rt, and after 64 h, treated with methanol and concentrated in vacuo to provide rac-(1R,2R)-2-bromocyclohexanamine that gave a mass ion (ES+) of 178.1 (⁷⁹Br) for [M+H]⁺.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting rac-(1R,2R)-2-bromocyclohexanamine for tetrahydro-2H-pyran-4-amine. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 548.1637 calculated for M+H⁺ [C₂₈H₃₁BrN₅O₂: 548.1656]: ¹H NMR (400 MHz, CDCl₃) δ 9.99 (d, J=8.0 Hz, 1H), 9.42 (d, J=7.1 Hz, 1H), 8.68 (s, 1H), 8.60-8.57 (m, 1H), 8.19 (d, J=8.9 Hz, 1H), 7.75-7.60 (m, 3H), 7.31-7.23 (m, 2H), 4.32-4.26 (m, 1H), 4.20-4.14 (m, 1H), 3.82 (s, 2H), 3.02-2.99 (m, 2H), 2.64-2.58 (m, 1H), 2.43-2.26 (m, 4H), 2.09-1.93 (m, 3H), 1.81-1.77 (m, 2H), 1.58-1.26 (m, 4H).

Example 14 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-hydroxy-2-methylcyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of rac-(1R,2R)-2-amino-1-methylcyclohexanol and rac-(1R,2R)-2-amino-2-methylcyclohexanol

To a solution of 1-methyl-1-cyclohexene (1.00 g, 10.4 mmol) in 35 mL of dichloromethane at 0° C. was added m-chloroperbenzoic acid (3.08 g, 12.5 mmol). After 1 h, the mixture was diluted with additional dichloromethane, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-5% ethyl acetate in hexanes to provide 1-methyl-7-oxabicyclo[4.1.0]heptane that gave a proton NMR spectra consistent with theory.

A solution of the above compound (0.203 g, 1.81 mmol) and sodium azide (0.294 g, 4.52 mmol) in 10 mL of a 1:1 mixture of acetone:water was heated to reflux at 75° C. for 14 h. The mixture was cooled to rt, concentrated in vacuo to 5 mL, and extracted 3× with diethyl ether. The combined organic fractions were washed 2× with water, dried over sodium sulfate, filtered, and concentrated in vacuo to provide a crude mixture of rac-(1R,2R)-2-azido-1-methylcyclohexanol and rac-(1R,2R)-2-azido-2-methylcyclohexanol.

To a solution of the above mixture (0.216 g, 1.39 mmol) in 7 mL of methanol was added palladium on carbon (10%, 0.222 g, 2.09 mmol). The mixture was placed under an atmosphere of hydrogen (1 atm) for 62 h and was then filtered through a pad of Celite, which was washed with 20% methanol in dichloromethane to provide a crude mixture of rac-(1R,2R)-2-amino-1-methylcyclohexanol and rac-(1R,2R)-2-amino-2-methylcyclohexanol.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting the crude mixture of rac-(1R,2R)-2-amino-1-methylcyclohexanol and rac-(1R,2R)-2-amino-2-methylcyclohexanol for tetrahydro-2H-pyran-4-amine. The crude product was subjected to purification via silica gel chromatography, eluting with 0-5% methanol in dichloromethane, followed by additional purification via reverse phase HPLC to provide the title compound. The resultant solid gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 500.0 for [M+H]⁺: ¹H NMR (400 MHz, CDCl₃) δ 9.65 (s, 1H), 9.41 (d, J=7.2 Hz, 1H), 8.70 (s, 1H), 8.58 (d, J=4.4 Hz, 1H), 7.92 (s, 1H), 7.73 (d, J=7.0 Hz, 1H), 7.50 (d, J=9.8 Hz, 1H), 7.39 (s, 1H), 7.25-7.22 (m, 1H), 4.48 (br s, 1H), 4.03 (br s, 1H), 3.60 (s, 2H), 3.69-3.07 (m, 3H), 2.32 (br s, 2H), 1.95-1.84 (m, 2H), 1.75-1.30 (m, 8H), 2.20 (s, 3H), 1.17-1.05 (m, 1H).

Example 15 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-[(1R)-2-oxocyclohexyl]-4H-quinolizine-3-carboxamide

1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-hydroxycyclohexyl]-4-oxo-4i-quinolizine-3-carboxamide was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting (1R,2R)-2-aminocyclohexanol for tetrahydro-2H-pyran-4-amine.

To a solution of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-hydroxycyclohexyl]-4-oxo-4i-quinolizine-3-carboxamide (0.022 g, 0.046 mmol) in 1 mL of dichloromethane containing crushed 4 Å molecular sieves at 0° C. was added 4-methylmorpholine N-oxide (7.0 mg, 0.060 mmol). After 15 min, tetrapropylammonium perruthenate (1.6 mg, 0.0046 mmol) was added. After 1 h, the mixture was warmed to rt and after 2 h, the mixture was recooled to 0° C., and additional 4-methylmorpholine N-oxide (7.0 mg, 0.060 mmol) and tetrapropylammonium perruthenate (1.6 mg, 0.0046 mmol) were added. The mixture was rewarmed to rt and after 16 h, subjected to purification via silica gel chromatography, eluting with 0-3% methanol in dichloromethane to provide the title compound gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 548.1637 calculated for M+H⁺ [C₂₈H₃₁BrN₅O₂: 548.1656]: ¹H NMR (400 MHz, CDCl₃) δ 9.49 (d, J=7.3 Hz, 1H), 8.62 (s, 1H), 8.60-8.58 (m, 1H), 8.17 (d, J=8.9 Hz, 1H), 7.75-7.65 (m, 2H), 7.61 (d, J=8.0 Hz, 1H), 7.31-7.23 (m, 2H), 4.83-4.77 (m, 1H), 3.81 (s, 2H), 3.02-2.99 (m, 2H), 2.76-2.70 (m, 1H), 2.63-2.56 (m, 3H), 2.51-2.44 (m, 1H), 2.43-2.25 (m, 2H), 2.19-2.09 (m, 1H), 2.06-1.93 (m, 2H), 1.91-1.84 (m, 2H), 1.76-1.64 (m, 1H), 1.60-1.54 (m, 1H).

Example 16 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylthio)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of rac-(1R,2R)-2-(methylthio)cyclohexanamine

To a solution of benzyl 7-azabicyclo[4.1.0]heptane-7-carboxylate (see Example 13, 0.273 g, 1.18 mmol) in 3 mL of THF was added eerie ammonium nitrate (0.065 g, 0.12 mmol) and sodium thiomethoxide (0.165 g, 2.36 mmol). After 30 min, 15-crown-5 (0.520 g, 2.36 mmol) was added. After 110 h, the reaction was concentrated in vacuo, diluted with water, and extracted 3× with diethyl ether. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-15% ethyl acetate in hexanes to provide benzyl rac-[(1R,2R)-2-(methylthio)cyclohexyl]carbamate that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 280.1 for [M+H]⁺.

To a solution of the above compound (0.165 g, 0.590 mmol) in 3 mL of a solution of methanol saturated with HCl_((g)) was added palladium hydroxide (0.207 g, 0.295 mmol). The mixture was placed under an atmosphere of hydrogen (1 atm) for 86 h and was then filtered through a pad of Celite, which was washed with methanol, and concentrated in vacuo to provide rac-(1R,2R)-2-(methylthio)cyclohexanamine.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting rac-(1R,2R)-2-(methylthio)cyclohexanamine for tetrahydro-2H-pyran-4-amine. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 516.2435 calculated for M+H⁺ [C₂₉H₃₄N₅O₂S: 516.2428]: ¹H NMR (400 MHz, CDCl₃) δ 9.93 (d, J=8.2 Hz, 1H), 9.43 (d, J=7.3 Hz, 1H), 8.68 (s, 1H), 8.60-8.58 (m, 1H), 8.60-8.58 (m, 1H), 8.18 (d, J=9.0 Hz, 1H), 7.75-7.71 (m, 1H), 7.67-7.60 (m, 2H), 7.29-7.22 (m, 1H), 4.12-4.09 (m, 1H), 3.81 (s, 2H), 3.02-2.99 (m, 2H), 2.72-2.66 (m, 1H), 2.63-2.57 (m, 2H), 2.32-2.01 (m, 6H), 1.77 (br s, 2H), 1.66-1.63 (m, 1H), 1.58 (s, 3H), 1.51-1.41 (m, 3H).

Example 17 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-{(1R,2R)-2-[(S)-methylsulfinyl]cyclohexyl}-4-oxo-4H-quinolizine-3-carboxamide

To a solution of rac-1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylthio)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide (Example 16, 0.035 g, 0.067 mmol) in 2 mL of dichloromethane at 0° C. was added 3-phenyl-2-(phenylsulfonyl)-1,2-oxaziridine (Davis reagent, 0.019 g, 0.074 mmol). After 45 min, the mixture was washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-5% methanol in dichloromethane to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 532.2390 calculated for M+H⁺ [C₂₉H₃₄N₅O₃S: 532.2377]: ¹H NMR (400 MHz, CDCl₃) δ 10.02-9.99 (m, 1H), 9.42-9.40 (m, 1H), 8.66 (s, 1H), 8.60-8.57 (m, 1H), 8.22-8.19 (m, 1H); 7.76-7.67 (m, 2H), 7.62-7.60, 7.32-7.21 (m, 1H), 4.29-4.26 (m, 1H), 4.13-4.03 (m, 1H), 3.81 (s, 2H), 3.01-2.83 (m, 2H), 2.82-2.78 (m, 1H), 2.61 (s, 3H), 2.47-2.43 (m, 1H), 2.32-2.26 (m, 2H), 2.14-2.06 (m, 4H), 2.05-1.84 (m, 2H), 1.83-1.36 (m, 2H).

Example 18 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylsulfonyl)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

To a solution of rac-1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylthio)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide (Example 16, 0.035 g, 0.067 mmol) in 1 mL of dichloromethane containing crushed 4 Å molecular sieves at 0° C. was added 4-methylmorpholine N-oxide (0.017 g, 0.14 mmol). After 15 min, tetrapropylammonium perruthenate (2.4 mg, 0.0068 mmol) was added. After 1 h, the mixture was warmed to rt and after 2 h, the mixture was recooled to 0° C., and additional 4-methylmorpholine N-oxide (7.0 mg, 0.060 mmol) and tetrapropylammonium perruthenate (1.6 mg, 0.0046 mmol) were added. The mixture was rewarmed to rt and after 16 h, filtered and concentrated in vacuo. The residue was subjected to purification via reverse phase HPLC to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) ink of 548.2343 calculated for M+H⁺ [C₂₉H₃₄N₅O₄S: 548.2326]: ¹H NMR (400 MHz, CDCl₃) δ 9.43 (d, J=7.1 Hz, 1H), 8.62 (s, 1H), 8.60-8.58 (m, 1H), 8.20 (d, J=9.0 Hz, 1H), 7.76-7.67 (m, 2H), 7.62-7.60 (m, 1H), 7.34-7.23 (m, 2H), 4.47-4.41 (m, 1H), 3.81 (s, 2H), 3.24-3.18 (m, 1H), 3.03-3.00 (m, 1H), 2.99 (s, 3H), 2.63-2.57 (m, 2H), 2.41-2.24 (m, 4H), 2.09-2.06 (m, 2H), 1.94-1.91 (m, 1H), 1.82-1.63 (m, 6H).

Example 19 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-3-yl-4H-quinolizine-3-carboxamide

tert-Butyl 3-[({1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizin-3-yl}carbonyl)amino]piperidine-1-carboxylate was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting tert-butyl 3-aminopiperidine-1-carboxylate for tetrahydro-2H-pyran-4-amine.

To a solution of tert-butyl 3-[({1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizin-3-yl}carbonyl)amino]piperidine-1-carboxylate (0.335 g, 0.587 mmol) in 12 mL of dichloromethane at 0° C. was added trifluoroacetic acid (1.17 mL, 15.2 mmol). The mixture was warmed to rt, and after 2 h, treated with saturated aqueous sodium bicarbonate and extracted 3× with dichloromethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 471.2504 calculated for M+H⁺ [C₂₇H₃₁N₆O₂: 471.2503]: ¹H NMR (400 MHz, CDCl₃) δ 9.93 (d, J=7.5 Hz, 1H), 9.38 (d, J=7.3 Hz, 1H), 8.60 (s, 1H), 8.55 (d, J=4.0 Hz, 1H), 8.14 (d, J=9.0 Hz, 1H), 7.71-7.61 (m, 2H), 7.56 (d, J=8.0 Hz, 1H), 7.27-7.19 (m, 2H), 4.21-4.18 (m, 1H), 3.78 (s, 2H), 3.30-3.27 (m, 1H), 3.00-2.76 (m, 4H), 2.63-2.53 (m, 3H), 2.29-2.21 (m, 2H), 2.05-1.86 (m, 3H), 1.85 (br s, 1H), 1.70-1.53 (m, 2H).

Example 20 Methyl 4-[({1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizin-3-yl}carbonyl)amino]piperidine-1-carboxylate

1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-4-yl-4H-quinolizine-3-carboxamide was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-3-yl-4H-quinolizine-3-carboxamide in Example 19, substituting tert-butyl 4-aminopiperidine-1-carboxylate for tert-butyl 3-aminopiperidine-1-carboxylate.

To a solution of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-4-yl-4H-quinolizine-3-carboxamide (0.027 g, 0.057 mmol) in 2 mL of dichloromethane was added triethylamine (0.3 mL, 2.1 mmol) followed by methyl chloroformate (0.10 mL, 1.3 mmol). After 1 h, the mixture was washed with 0.5 N aqueous sodium hydroxide and brine, dried over sodium sulfate, filtered, and concentrated in vacuo to provide the title compound that gave a proton NMR spectra consistent with theory: ¹H NMR (400 MHz, CDCl₃) δ 9.80 (d, J=7.7 Hz, 1H), 9.40 (d, J=7.3 Hz, 1H), 8.65 (s, 1H), 8.60-8.58 (m, 1H), 8.19 (d, J=8.9 Hz, 1H), 7.76-7.66 (m, 2H), 7.62-7.59 (m, 1H), 7.32-7.23 (m, 2H), 4.24-4.21 (m, 1H), 4.03 (br s, 1H), 3.82 (s, 2H), 3.71 (s, 3H), 3.69-3.61 (m, 2H), 3.15-3.09 (m, 1H), 3.02-2.98 (m, 1H), 2.60-2.57 (m, 1H), 2.55-2.50 (m, 2H), 2.32-2.25 (m, 1H), 2.09-2.02 (m, 2H), 1.93 (br s, 1H), 1.59-1.52 (m, 1H), 1.40-1.37 (m, 2H), 1.06-1.01 (m, 3H).

Example 21 rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(3R,4S)-3-methyltetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of rac-(3R,4S)-3-methyltetrahydro-2H-pyran-4-amine

To a solution of lithium diisopropylamide (1.8 M in THF, 30.5 mL, 54.9 mmol) in 200 mL of THF at −78° C. was added a solution of tetrahydro-4H-pyran-4-one (5.00 g, 49.9 mmol) in 20 mL of THF dropwise. After 15 min, iodomethane (6.25 mL, 0.100 mol) was added and the reaction was slowly warmed to rt. After 15 h, the mixture was treated with saturated aqueous ammonium chloride and extracted 2× with diethyl ether. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-30% ethyl acetate in hexanes to provide 3-methyltetrahydro-4H-pyran-4-one that gave a proton NMR spectra consistent with theory.

To a solution of lithium tri-sec-butylborohydride (1.0 M in THF, 18.6 mL, 18.6 mmol) in 10 mL of THF at 0° C. was added a solution of the above compound (1.70 g, 14.9 mmol) in 10 mL of THF dropwise. After 30 min, the reaction was treated with saturated aqueous ammonium chloride and extracted 2× with dichloromethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 10-40% ethyl acetate in hexanes to provide rac-(3R,4S)-3-methyltetrahydro-2H-pyran-4-ol that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (0.850 g, 7.32 mmol) in 75 mL of THF at −20° C. under an atmosphere of nitrogen was added triphenylphosphine (9.60 g, 36.6 mmol), diethyl azodicarboxylate (DEAD, 6.37 g, 36.6 mmol), and diphenylphosphoryl azide (10.1 g, 36.6 mmol). After 6 h, the reaction was warmed to rt, and after an additional 15 h, diluted with water and extracted 2× with ethyl acetate. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-30% ethyl acetate in hexanes to provide rac-(3R,4S)-4-azido3-methyltetrahydro-2H-pyran that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (0.350 g, 2.48 mmol) in 12 mL of methanol was added palladium on carbon (10%, 0.175 g, 0.164 mmol). The mixture was placed under an atmosphere of hydrogen (1 atm) for 3 h and was then filtered through a pad of Celite, which was washed with MeOH. The filtrate was concentrated in vacuo, and the residue was treated with 1 M hydrochloric acid and extracted 3× with dichloromethane. The aqueous solution was treated with solid sodium hydroxide to pH 10 and extracted 3× with dichloromethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 0-30% ethyl acetate in hexanes to provide rac-(3R,4S)-3-methyltetrahydro-2H-pyran-4-amine that gave a proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting rac-(3R,4S)-3-methyltetrahydro-2H-pyran-4-amine for tetrahydro-2H-pyran-4-amine. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 486.2498 calculated for M+H⁺ [C₂₈H₃₂N₅O₃: 486.2500]: ¹H NMR (400 MHz, CDCl₃) δ 9.66 (d, J=8.4 Hz, 1H), 9.38 (d, J=7.0 Hz, 1H), 8.64 (s, 1H), 8.56-8.54 (m, 1H), 8.16 (d, J=9.0 Hz, 1H), 7.80-7.41 (m, 3H), 7.38-7.09 (m, 2H), 4.09-3.88 (m, 3H), 3.78 (s, 2H), 3.55-3.48 (m, 1H), 3.17-3.11 (m, 1H), 3.04-2.95 (m, 2H), 2.28-2.22 (m, 2H), 2.05-2.00 (m, 3H), 1.84-1.72 (m, 1H), 1.67-1.56 (m, 1H), 0.90 (d, 6.7 Hz, 3H).

Example 22 1-{[4-Cyano-4-(4-cyanopyridin-2-yl)piperidin-1-yl]methyl}-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

To a solution of 2-fluoro-4-iodopyridine (7.27 g, 22.2 mmol) in 25 mL of toluene under an atmosphere of nitrogen was added hexamethylditin (4.50 g, 20.2 mmol) and tetrakis(triphenylphosphine)palladium(0) (2.33 g, 2.02 mmol). The mixture was heated to 120° C. in a sealed flask for 15 h, cooled to rt, filtered through silica gel, and concentrated in vacuo. The residue was purified via silica gel chromatography, eluting with 5-20% ethyl acetate in hexanes to provide 2-fluoro-4-(trimethylstannyl)pyridine that gave a proton NMR spectra consistent with theory.

A mixture of tert-butyl 4-cyanopiperidine-1-carboxylate (4.21 g, 20.0 mmol) and the above compound (4.00 g, 15.4 mmol) was dissolved in 80 mL of THF. The reaction was purged with a stream of nitrogen and cooled to −78° C. To this mixture was added 1 M lithium bis(trimethylsilyl)amide in THF (1.47 mL, 1.47 mmol), and the resultant solution was stirred at this temperature for 1 h. The reaction was warmed to ambient temperature, stirred for 15 h, and quenched with a saturated ammonium chloride solution. The mixture was extracted 3× with ethyl acetate and the combined organic extracts were dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to silica gel chromatography eluting with 5-20% EtOAc in hexanes to provide tert-butyl-4-cyano-4-[4-(trimethylstannyl)pyridine-2-yl]piperidine-1-carboxylate.

To a solution of the above compound (3.24 g, 7.20 mmol) in 100 mL of dichloromethane at 0° C. under an atmosphere of nitrogen was added N-iodosuccinimide (2.10 g, 9.36 mmol). After 15 h, additional N-iodosuccinimide (0.600 g, 2.67 mmol) was added. After 6 h, the reaction was treated with saturated aqueous sodium thiosulfate, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to provide tert-butyl 4-cyano-4-(4-iodopyridin-2-yl]piperidine-1-carboxylate that gave a proton NMR spectra consistent with theory.

1-{[4-Cyano-4-(4-iodopyridin-2-yl)piperidin-1-yl]methyl}-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide was prepared by the procedure described for the synthesis of 1-({4-[6-(difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide in Example 5, substituting tert-butyl 4-cyano-4-(4-iodopyridin-2-yl)piperidine-1-carboxylate for tert-butyl 4-[6-(difluoromethyl)pyridine-3-yl]piperazine-1-carboxylate. The resultant yellow solid gave a mass ion (ES+) of 611.9 for [M+H]⁺.

To a solution of the above compound (0.046 g, 0.075 mmol) in 1 mL of acetonitrile was added sodium cyanide (7.3 mg, 0.15 mmol), tributyltin chloride (0.24 mg, 0.75 μmol), and bis(tri-tert-butylphosphine)palladium(0) (3.8 mg, 0.75 μmol). The mixture was heated to 100° C. for 1 h, cooled to rt, and diluted with dichloromethane. The organic solution was washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via reverse phase HPLC to provide the title compound that gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 511.2469 calculated for M+H⁺ [C₂₉H₃₁N₆O₃: 511.2452]: ¹H NMR (400 MHz, CDCl₃) δ 9.84 (d, J=5.9 Hz, 1H), 9.42 (d, J=47.4 Hz, 1H), 8.79 (d, J=4.9 Hz, 1H), 8.67 (s, 1H), 8.17 (d, J=8.9 Hz, 1H), 7.83 (s, 1H), 7.74-7.70 (m, 1H), 7.51 (d, J=3.6 Hz, 1H), 7.35-7.31 (m, 1H), 3.89 (br s, 1H), 3.66-3.41 (m, 4H), 3.65 (s, 2H), 3.10 (br s, 1H), 2.68 (br s, 1H), 2.13-2.09 (m, 2H), 1.78-1.25 (m, 7H), 0.88-0.85 (m, 2H).

Example 23 1-({4-Cyano-4-[4-(fluoromethyl)pyridine-2-yl]piperidin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of tert-butyl 4-cyano-4-[4-(fluoromethyl)pyridine-2-yl]piperidine-1-carboxylate

To a solution of (2-chloropyridin-4-yl)methanol (0.307 g, 2.14 mmol) in 20 mL of DMF at 0° C. under an atmosphere of nitrogen was added tert-butyldimethylchlorosilane (0.355 g, 2.35 mol) and imidazole (0.160 g, 2.35 mmol). After 1 h, the mixture was diluted with water, washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to silica gel chromatography eluting with 0-15% EtOAc in hexanes to provide 4-({[tert-butyl(dimethyl)silyl]oxy}methyl)-2-chloropyridine that gave a mass ion (ES+) of 258.1 for [M+H]⁺.

A mixture of tert-butyl 4-cyanopiperidine-1-carboxylate (418 mg, 1.62 mmol) and 2-4-({[tert-butyl(dimethyl)silyl]oxy}methyl)-2-chloropyridine (0.284 mL, 1.35 mmol) was dissolved in 10 mL of THF. The reaction was purged with a stream of nitrogen and cooled to −78° C. To this reaction was added lithium bis(trimethylsilyl)amide (1.0 M in THF, 1.89 mL, 1.89 mmol), which was stirred for 1 h. The reaction was warmed to ambient temperature, stirred for 62 h, and quenched with a saturated ammonium chloride solution. The mixture was extracted 3× with dichloromethane. The combined organic extracts were dried over sodium sulfate, filtered, concentrated in vacuo, and subjected to silica gel chromatography eluting with 0-20% EtOAc in hexanes to provide tert-butyl 4-[4-({[tert-butyl(dimethyl)silyl]oxy}methyl)pyridine-2-yl]-4-cyanopiperidine-1-carboxylate that gave a proton NMR spectra consistent with theory.

To a solution of the above compound (0.237 g, 0.549 mmol) in 3 mL of THF under an atmosphere of nitrogen was added tetrabutylammonium fluoride (1.0 M in THF, 0.58 mL, 0.58 mmol) dropwise. After 2 h, the mixture was treated with saturated aqueous sodium bicarbonate and diluted with dichloromethane. The organic solution was washed 3× with water, dried over sodium sulfate, filtered, and concentrated in vacuo to provide tert-butyl 4-cyano-4-[4-(hydroxymethyl)pyridin-2-yl]piperidine-1-carboxylate.

To a solution of above compound (0.194 g, 0.611 mmol) in 3 mL of dichloromethane at −78° C. was added [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxofluor, 0.14 mL, 0.67 mmol) dropwise. The reaction was warmed to 0° C. and after 3 h, the reaction was recooled to −78° C. and additional [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxofluor, 0.072 mL, 0.34 mmol) was added. The mixture was rewarmed to rt and after 7 h, treated with water and extracted 3× with dichloromethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The resultant residue was subjected to purification via silica gel chromatography, eluting with 0-30% ethyl acetate in hexanes to provide tert-butyl 4-cyano-4-[4-(fluoromethyl)pyridine-2-yl]piperidine-1-carboxylate that gave a proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-({4-[6-(difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide in Example 5, substituting tert-butyl 4-cyano-4-[4-(fluoromethyl)pyridine-2-yl]piperidine-1-carboxylate for tert-butyl 4-[6-(difluoromethyl)pyridine-3-yl]piperazine-1-carboxylate. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 518.2575 calculated for M+H⁺ [C₂₉H₃₃FN₅O₃: 518.2562]: ¹H NMR (400 MHz, CDCl₃) δ 9.87 (d, J=6.4 Hz, 1H), 9.41 (d, J=7.2 Hz, 1H), 8.66 (s, 1H), 8.60 (d, J=5.0 Hz, 1H), 8.19 (d, J=9.0 Hz, 1H), 7.72-7.68 (m, 1H), 7.55 (s, 1H), 7.33-7.22 (m, 2H), 5.44 (d, J=46.6 Hz, 2H), 4.35 (br s, 1H), 3.90-3.85 (m, 1H), 3.82 (s, 2H), 3.53-3.49 (m, 1H), 3.02-2.98 (m, 2H), 2.64-2.57 (m, 2H), 2.33-2.27 (m, 2H), 2.13-2.04 (m, 3H), 1.78-1.75 (m, 2H), 1.53-1.24 (m, 4H).

Example 24 1-({4-Cyano-4-[4-(difluoromethyl)pyridin-2-yl]piperidin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide

Synthesis of tert-butyl 4-cyano-4-[4-(difluoromethyl)pyridine-2-yl]piperidine-1-carboxylate

To a solution of tert-butyl 4-cyano-4-[4-(hydroxymethyl)pyridine-2-yl]piperidine-1-carboxylate (see Example 23, 0.465 g, 1.46 mmol) in 7 mL of acetonitrile was added 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (1.23 g, 4.39 mmol). The mixture was heated to 80° C. for 1 h, cooled to rt, and filtered through a glass frit. The filter cake was washed 3× with dichloromethane and the organic filtrate was concentrated in vacuo. The resultant residue was subjected to silica gel chromatography eluting with 0-30% EtOAc in hexanes to provide tert-butyl 4-cyano-4-(4-formylpyridin-2-yl)piperidine-1-carboxylate that gave a proton NMR spectra consistent with theory.

To a solution of above compound (0.300 g, 0.951 mmol) in 5 mL of dichloromethane at −78° C. under an atmosphere of nitrogen was added [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxofluor, 0.31 mL, 1.4 mmol) dropwise. The reaction was warmed to rt and after 18 h, the reaction was treated with water and extracted 3× with dichloromethane. The combined organic fractions were washed 2× with water, dried over sodium sulfate, filtered, and concentrated in vacuo to provide ethyl 9-methyl-4-oxo-4H-quinolizine-3-carboxylate to provide tert-butyl 4-cyano-4-[4-(difluoromethyl)pyridine-2-yl]piperidine-1-carboxylate that gave a proton NMR spectra consistent with theory.

The title compound was prepared by the procedure described for the synthesis of 1-({4-[6-(difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide in Example 5, substituting tert-butyl 4-cyano-4-[4-(difluoromethyl)pyridine-2-yl]piperidine-1-carboxylate for tert-butyl 4-[6-(difluoromethyl)pyridine-3-yl]piperazine-1-carboxylate. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 536.2473 calculated for M+H⁺ [C₂₉H₃₂F₂N₅O₃: 536.2468]: ¹H NMR (400 MHz, CDCl₃) δ 9.87 (d, J=6.2 Hz, 1H), 9.41 (d, J=7.2 Hz, 1H), 8.72 (d, J=5.1 Hz, 1H), 8.66 (s, 1H), 8.18 (d, J=8.8 Hz, 1H), 7.72-7.68 (m, 2H), 7.39-7.33 (m, 1H), 7.32-7.29 (m, 1H), 7.65 (t, J=55.6 Hz, 1H), 4.34 (br s, 1H), 3.90-3.85 (m, 1H), 3.82 (s, 2H), 3.54-3.51 (m, 1H), 3.03-3.00 (m, 2H), 2.64-2.58 (m, 2H), 2.33-2.26 (m, 2H), 2.11-2.08 (m, 4H), 1.78-1.75 (m, 2H), 1.48-1.26 (m, 4H).

Example 25 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-9-methyl-4-oxo-N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide

To a solution of lithium diisopropylamide (1.8 M in THF, 64.8 mL, 117 mmol) in 135 mL of THF at −78° C. was added a solution of 2,3-lutidine (10.0 g, 93.0 mol) in 62 mL of THF dropwise over 10 min. After an additional 40 min, a solution diethyl ethoxymethylenemalonate (21.7 mL, 107 mmol) in 30 mL of THF was added slowly over 15 min, and the reaction was slowly warmed to rt. After 2.5 h, the mixture was treated with saturated aqueous ammonium chloride and extracted 3× with dichlormethane. The combined organic fractions were dried over sodium sulfate, filtered, and concentrated in vacuo. The crude intermediate was dissolved in 100 mL of o-xylene and heated to reflux for 16 h. The reaction was concentrated in vacuo and the resultant residue was purified via silica gel chromatography, eluting with 0-5% methanol in dichloromethane to provide ethyl 9-methyl-4-oxo-4H-quinolizine-3-carboxylate that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 232.1 for [M+H]⁺.

To a solution of the above compound (15.3 g, 66.2 mmol) in 100 mL of DMF at 0° C. was added phosphorous oxychloride (15.4 mL, 165 mmol) dropwise via an addition funnel. The reaction was warmed to rt, and after 20 h, quenched by pouring onto 300 mL of ice water with stirring. A yellow-brown precipitate was collected via filtration and washed with water and diethyl ether to provide ethyl 1-formyl-9-methyl-4-oxo-4H-quinolizine-3-carboxylate that gave a proton NMR spectra consistent with theory and a mass ion (ES+) of 260.1 for [M+H]⁺.

The title compound was prepared by the procedure described for the synthesis of 1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide in Example 1, substituting ethyl 1-formyl-9-methyl-4-oxo-4H-quinolizine-3-carboxylate for ethyl 1-formyl-4-oxo-4H-quinolizine-3-carboxylate. The resultant yellow solid gave a proton NMR spectra consistent with theory and a high resolution mass spectrum (ES+) m/z of 486.2501 calculated for M+H⁺ [C₂₈H₃₂N₅O₃: 486.2500]: ¹H NMR (400 MHz, CDCl₃) δ 9.70 (d, J=7.6 Hz, 2H), 9.43 (d, J=7.3 Hz, 1H), 8.55-8.53 (m, 2H), 7.71-7.67 (m, 1H), 7.59-7.56 (m, 1H), 7.45-7.43 (m, 1H), 7.23-7.12 (m, 2H), 4.25-4.20 (m, 1H), 4.00-3.94 (m, 2H), 3.87 (s, 2H), 3.58-3.51 (m, 2H), 2.94-2.90 (m, 2H), 2.58-2.51 (m, 2H), 2.26-2.19 (m, 2H), 2.11-1.99 (m, 4H), 1.70-1.64 (m, 2H).

The following compounds in Table 1 were prepared according to referenced procedure, and in the Examples above. The starting materials are either commercially available or known in the literature, or may be prepared from commercially available reagents using conventional reactions well known in the art.

TABLE 1 Compounds of Formula (IA)

Example No. Chirality R^(B) R^(A) M + H Method 26 (1S, 2S)

454.0 Example 2/3 27 (1S, 2S)

454.9 Example 3 28 (1S, 2S)

457.0 Example 2/3 29 (1S, 2S)

527.9 Example 1 30 (1S, 2S)

518.0 Example 1 31 (1S, 2S)

528.9 Example 1 32 (1R, 2R)

528.9 Example 1 33 (1S, 2S)

486.0 Example 1 34 (1R, 2R)

486.0 Example 1 35 (1S, 2S)

462.0 Example 1 36 (1S, 2S)

487.0 Example 5 37 (1S, 2S)

487.0 Example 5 38 (1S, 2S)

530.0 Example 5 39 (1S, 2S)

476.0 Example 5 40 (1S, 2S)

492.0 Example 5 41 (1S, 2S)

512.1 Example 5 42 (3R, 4S)

513.9 Example 5 43 (3S, 4S)

514.2 Example 5 44 (1S, 2S)

581.0 Example 5 45 (1S, 2S)

543.1 Example 5 46 (1S, 2S)

547.0 Example 5 47 (1S, 2S)

592.9 (⁸¹Br) Example 5 48 (1S, 2S)

544.0 Example 1 49 (1S, 2S)

526.0 Example 1 50 (1S, 2S)

518.0 Example 5 51 (1S, 2S)

465.1 Example 5 52 (1S, 2S)

485.0 Example 1 53 (1S, 2S)

503.0 Example 1 54 (1S, 2S)

518.9 Example 1 55 (1S, 2S)

499.0 Example 1 56 (1S, 2S)

553.0 Example 1 57 (1S, 2S)

515.2 Example 1 58 (1S, 2S)

502.9 Example 1 59

428.0 Example 1 60

442.0 Example 1 61

456.0 Example 1 62

470.0 Example 1 63

468.0 Example 1 64

468.24 Example 1 65 Trans racemic

488.0 Example 1 66 (1S, 2S)

488.0 Example 1 67 (1R, 2R)

488.0 Example 1 68 Racemic

506.0 Example 1 69 Racemic (cis & trans)

484.0 Example 1 70 (1S, 2S)

485.97 Example 1 71 (1R, 2R)

485.97 Example 1 72 Cis racemic

486.0 Example 1 73 Trans racemic

500.0 Example 16 74 Trans racemic

514.1 Example 16 75

484.0 Example 1 76 Trans

486.25 Example 1 77 Cis

486.25 Example 1 78

N/A Example 19 79

485.4 Example 1 80

573.6 Example 20 81

485.27 Example 1 82

513.3 Example 1 83 Racemic

472.0 Example 1 84 (3R, 4S)

488.2 Example 10 85

500.0 Example 1 86

486.0 Example 1 87

488.0 Example 1 88 cis & trans

504.0 Example 1 89

478.0 Example 1 90

479.0 Example 1 91

465.0 Example 1 92

468.97 Example 1 93

498.0 Example 1 94

498.0 Example 1 95

498.0 Example 1 96

498.0 Example 1 97 (1S, 2S)

500.0 Example 1 98

486.0 Example 1 99 (3R, 4S)

502.3 Example 11 100 (3R, 4S)

502.3 Example 10 101 (1S, 2S)

500.1 Example 1 102 (3R, 4S)

645.8 Example 1 103 (1S, 2S)

465.9 Example 1 104 (1S, 2S) Eluent a

509.1 Example 1 105 (1S, 2S) Eluent b

509.1 Example 1 106

388.0 Example 1 107

402.0 Example 1 108

416.2 Example 1 109

430.2 Example 1 110

430.2 Example 1 111

444.2 Example 1 112

444.2 Example 1 113

416.2 Example 1 114

428.2 Example 1 115

456.2 Example 1 116

470.3 Example 1 117

464.2 Example 1 118

442.2 Example 1 119

456.2 Example 1 120

457.2 Example 1 121

458.2 Example 1 122

432.2 Example 1 123

469.2 Example 1 124

456.2 Example 1 125

388.0 Example 1 126

401.95 Example 1 127

431.98 Example 1 128

427.9 Example 1 129

504.0 Example 1 130

518.0 Example 1 131

468.97 Example 1

The following compounds in Table 2 were prepared according to the referenced procedure, and the Examples above. The starting materials are either commercially available or known in the literature, or may be prepared from commercially available reagents using conventional reactions well known in the art.

TABLE 2 (IB)

Compounds of Formula (IB) Example No. Chirality R^(B) R^(A) M + H Method 132 (1S, 2S)

500.0 Example 25 133 Trans racemic

515.9 Example 25 134 (1S, 2S)

513.9 Example 25 135

499.9 Example 25 Biological Utility

The utility of the compounds as M1 receptor positive allosteric modulators may be demonstrated by methodology known in the art, including by the assay described below. The assay is designed to select compounds that possess modulator activity at the acetylcholine muscarinic M1 receptor or other muscarinic receptors expressed in CHOnfat cells by measuring the intracellular calcium with a FLIPR³⁸⁴ Fluorometric Imaging Plate Reader System. The assay studies the effect of one or several concentrations of test compounds on basal or acetylcholine-stimulated Ca²⁺ levels using FLIPR.

Compounds are prepared and subjected to a preincubation period of 4 min. Thereafter, a single EC₂₀ concentration of acetylcholine is added to each well (3 nM final). The intracellular Ca²⁺ level of each sample is measured and compared to an acetylcholine control to determine any modulatory activity.

Cells: CHOnfat/hM1, hM2, hM3 or hM4 cells are plated 24 hr before the assay at a density of 18,000 cells/well (100 μL) in a 384 well plate. CHOnfat/hM1 and CHOnfat/hM3 Growth Medium: 90% DMEM (Hi Glucose); 10% HI FBS; 2 mM L-glutamine; 0.1 mM NEAA; Pen-Strep; and 1 mg/ml Geneticin, are added. For M2Gqi5CHOnfat and M4Gqi5CHOnfat cells, an additional 600 μg/ml hygromycin is added.

Equipment: 384 well plate, 120 μL addition plate; 96-well Whatman 2 ml Uniplate Incubator, 37° C., 5% CO₂; Skatron EMBLA-384 Plate Washer; Multimek Pipetting System; Genesis Freedom 200 System; Mosquito System; Temo Nanoliter Pipetting System; and FLIPR³⁸⁴ Fluorometric Imaging Plate Reader System are used.

Buffers. Assay Buffer: Hanks Balanced Salt Solution, with 20 mM Hepes, 2.5 mM Probenecid (Sigma P-8761) first dissolved in 1 N NaOH, 1% Bovine Serum Albumin (Sigma A-9647). Dye Loading Buffer: Assay Buffer plus 1% Fetal Bovine Serum and Fluo-4AM/Pluronic Acid Mixture. 2 mM Fluo-4AM ester stock in DMSO (Molecular Probes F-14202) Concentration of 2 μM in buffer for a final concentration of 1 μM in Assay. 20% Pluronic Acid Solution stock, with concentration of 0.04% in Buffer, 0.02% in Assay.

65 μL of 2 mM Fluo-4AM are mixed with 130 μL of 20% Pluronic Acid. The resulting solution and 650 μL FBS is added to the assay buffer for a total volume of 65 mL. Positive Controls: 4-Br-A23187: 10 mM in DMSO; final concentration 10 μM. Acetylcholine: 10 mM in water, working stock at both 20 μM and 30 μM in assay buffer, final concentration of 10 μM. This is used to check the maximum stimulation of the CHOK1/hM1 cells. 20 μM (2×) acetylcholine is added in the preincubation part of the assay, and the 30 μM (3×) stock is added in the second part. (EC₂₀) Acetylcholine: 10 mM in water, working stock of 9 nM (3×), and final concentration in assay is 3 nM. This is used after the preincubation with test compounds. Addition of the EC₂₀ Acetylcholine to each well with a test compound will ascertain any modulator activity. 24 wells contain 3 nM Acetylcholine alone as a control.

Determining Activity of Putative Compounds:

Screening Plate: Compounds are titrated in 96-well plates (columns 2-11), 100% DMSO, started at a concentration of 15 mM (150× stock concentration), and 3-fold serial dilutions using Genesis Freedom200 System. Four 96-well plates are combined into a 384-well plate using Mosquito Nanoliter Pipetting System by transferring 1 μl of serial diluted compounds to each well, and 1 mM acetylcholine (100× stock concentration) were added as a control. Using Temo, 49 μl assay buffer is added to each well of the 384-well plate right before assay.

In a 96-well Whatman 2 ml Uniplate, 9 nM Acetylcholine (3×) is pipetted into wells corresponding to the screening compounds, and into control wells. The 30 μM acetylcholine control (3×) is added into control wells, and the 3× agonist plate is transferred into a 384 well plate.

Cells are washed three times with 100 μL of buffer, leaving 30 μL of buffer in each well. Using Multimek, 30 μL of Dye Loading Buffer is added into each well and incubated at 37° C., 5% CO₂ for up to one hr.

After 60 min, the cells are washed three times with 100 μL of buffer, leaving 30 μL of buffer in each well. The cell plate, screening plate, and agonist addition plates are placed on the platform in the FLIPR and the door closed. A signal test to check background fluorescence and basal fluorescence signal is performed. Laser intensity is adjusted if necessary.

4 min of preincubation with the test compounds is provided to determine any agonist activity on the M1 receptor by comparison to the 1 mM acetylcholine control. After preincubation, the EC₂₀ value of acetylcholine (3 nM final) is added to determine any modulator activity.

A further description of the muscarinic FLIPR assay can be found in International patent application WO2004/073639.

In particular, the compounds of the following examples had activity in the aforementioned assay, generally with an IP (inflection point) of 10 μM (10,000 nM) or less. The inflection point is calculated from the FLIPR values, and is a measure of activity. Such a result is indicative of the intrinsic activity of the compounds in use as M1 allosteric modulators.

IP values from the aforementioned assay for representative exemplary compounds of the invention (as described herein) are provided below in Table 1 below:

Example IP Value (nM) 1 340 2 105 3 15 4 444 5 210 6 170 7 25 8 220 9 530 10 14 11 560 12 24 13 480 14 93 15 660 16 180 17 2600 18 800 19 1800 20 600 21 380 22 280 23 34 24 25 25 2100

The following abbreviations are used throughout the text:

-   Me: methyl -   Et: ethyl -   Bu: butyl -   t-Bu: tert-butyl -   i-Pr: isopropyl -   Ar: aryl -   Ph: phenyl -   Bn: benzyl -   Bz: benzoyl -   Ac: acetyl -   NaHMDS: Sodium hexamethyldisilazane -   MtBE: methyl tert-butyl ether -   NAD: nicotinamide adenine dinucleotide -   PLP: Pyridoxal phosphate -   LDH: Lactate dehydrogenase -   FDH: Formate dehydrogenase -   THF: tetrahydrofuran -   DBU: 2,4-diaminobutyric acid -   TPAP: tetrapropylammonium perruthenate -   NMO: 4-methylmorpholine N-oxide -   mCPBA: m-chloroperbenzoic acid -   DCE: dichloroethane -   DMF: dimethylformamide -   DME: 1,2-dimethoxyethane -   TES: triethylsilyl -   TFA: trifluoroacetic acid -   TEA: triethylamine -   IBX: iodobenzoic acid -   LDA: lithium diisopropylamide -   DMSO: dimethylsulfoxide -   DMEM: Dulbecco's Modified Eagle Medium (High Glucose) -   FBS: fetal bovine serum -   Bop: benzotriazol-1-yloxy-tris(dimethylamino)phosphonium     hexafluorophosphate -   Boc: t-butyloxycarbonyl -   rt: room temperature -   aq: aqueous -   HPLC: high performance liquid chromatography -   MS: mass spectrometry

While the invention has been described and illustrated with reference to certain particular embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures and protocols may be made without departing from the spirit and scope of the invention. It is intended, therefore, that the invention be defined by the scope of the claims that follow and that such claims be interpreted as broadly as is reasonable. 

What is claimed is:
 1. A compound of formula (I):

wherein R¹ is selected from the group consisting of (1) hydrogen, or (2) —C₁₋₆ alkyl, R² is selected from the group consisting of (1) hydrogen, (2) —C₁₋₆ alkyl, (3) —C₂₋₆ alkenyl, (4) —OC₁₋₆ alkyl, (5) —C₃₋₈ cycloalkyl, (6) —C₅₋₈ cycloalkenyl, (7) a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, (8) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, or (9) —C₆₋₁₀ aryl, wherein the alkyl, cycloalkyl, cycloalkenyl, heterocyclic, heteroaryl or aryl R2 moiety is optionally substituted by one or more (a) halogen, (b) hydroxyl, (c) —C₁₋₆ alkyl, (d) —O—C₁₋₆ alkyl, (e) —C₃₋₈ cycloalkyl, (f) —C₆₋₁₀ aryl, (g) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or (h) —(C═O)—C₁₋₆ alkyl, (i) —NR^(A)R^(B), wherein R^(A) and R^(B) are selected from the group consisting of (i) hydrogen, or (ii) —C₁₋₆ alkyl, or R^(A) and R^(B) are linked together with the nitrogen to which they are attached to form a 4-6 membered carbocyclic ring, wherein one or two of the ring carbon atoms is optionally replaced by a nitrogen, oxygen or sulfur, and the ring is optionally substituted with one or more (i) halogen, (ii) hydroxyl, (iii) C₁₋₆ alkyl, (iv) —O—C₁₋₆ alkyl, (v) —C(═O)—(O)_(n)—C₁₋₆ alkyl, or R¹ and R² are linked together with the nitrogen to which they are both attached to form a 4-8 membered saturated or unsaturated carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, and the carbocyclic is optionally substituted with one or more (a) halogen, (b) hydroxyl, (c) —C₁₋₆ alkyl, (d) —O—C₁₋₆ alkyl, (e) —C₃₋₈ cycloalkyl, (f) —C₆₋₁₀ aryl, (g) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, or (h) —(C═O)—C₁₋₆ alkyl; R³ is optionally present at one or more of the phenyl moiety C atoms, and is selected from the group consisting of (1) —C₁₋₆ alkyl, (2) —OC₁₋₆ alkyl, or (3) halogen; R⁴ is selected from the group consisting of (1) a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, (2) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, (3) —C₃₋₈ cycloalkyl, (4) —C₅₋₈ cycloalkenyl, or (5) —C₆₋₁₀ aryl, wherein the heterocyclic, heteroaryl or aryl moiety is optionally substituted with one or more (a) halogen, (b) hydroxyl, (c) —C₁₋₆ alkyl, (d) —O—C₁₋₆ alkyl, (e) —C₃₋₈ cycloalkyl, (f) —C₆₋₁₀ aryl, (g) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, or wherein the alkyl, cycloalkyl, aryl or heteroaryl moiety is optionally substituted with one or more (i) halogen, (ii) hydroxyl, (iii) —C₁₋₆ alkyl, or (iv) —O—C₁₋₆ alkyl, or a pharmaceutically acceptable salt thereof, provided when R² is a heterocyclic or heteroaryl group that is tetrazole then R⁴ is not an aryl that is phenyl.
 2. A compound of claim 1, wherein R¹ is hydrogen, or a pharmaceutically acceptable salt thereof.
 3. A compound of claim 1, wherein R² is —C₃₋₈ cycloalkyl, or a pharmaceutically acceptable salt thereof.
 4. A compound of claim 1, wherein R² is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 5. A compound of claim 1, wherein R² is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, or a pharmaceutically acceptable salt thereof.
 6. A compound of claim 1, wherein or R¹ and R² are linked together with the nitrogen to which they are both attached to form a 4-8 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, or a pharmaceutically acceptable salt thereof.
 7. A compound of claims 1 wherein R³ is absent or is methyl at the following position:

or a pharmaceutically acceptable salt thereof.
 8. A compound of claim 1 wherein R⁴ is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 9. A compound of claim 1 wherein R⁴ is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 10. A compound of claim 1 wherein R⁴ is —C₆₋₁₀ aryl, or a pharmaceutically acceptable salt thereof.
 11. A compound of claim 1, wherein the compound of formula (I) is a compound of formula (II)

or a pharmaceutically acceptable salt thereof, wherein R³ and R⁴ are as defined in claim
 1. 12. A compound of claim 11, wherein R⁴ is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 13. A compound of claim 11, wherein R⁴ is heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 14. A compound of claim 1, wherein the compound of formula (I) is a compound of formula (III)

or a pharmaceutically acceptable salt thereof, wherein R¹, R² and R³ are defined in claim 1, and R⁶ is selected from the group consisting of (1) halogen, (2) hydroxyl, (3) —C₁₋₆ alkyl, (4) —O—C₁₋₆ alkyl, (5) —C₃₋₈ cycloalkyl, (6) —C₆₋₁₀ aryl, (7) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, wherein the alkyl, cycloalkyl, aryl or heteroaryl moiety is optionally substituted with one or more (a) halogen, (b) hydroxyl, (c) —C₁₋₆ alkyl, (d) —O—C₁₋₆ alkyl.
 15. A compound of claim 14, wherein R⁶ is selected from the group consisting of (1) —C₆₋₁₀ aryl, or (2) heteroaryl, which is an aromatic cyclic or polycyclic group, having from five to twelve ring atoms, said ring atoms selected from C, O, N, N→O, C(═O) or S, at least one of which is O, N, N→O or S, wherein the aryl or heteroaryl moiety is optionally substituted with one or more (a) halogen, (b) hydroxyl, (c) —C₁₋₆ alkyl, (d) —O—C₁₋₆ alkyl, (e) —CN, wherein the alkyl moiety is optionally substituted with one or more halogen, or a pharmaceutically acceptable salt thereof.
 16. A compound of claim 15, wherein R¹ is hydrogen, or a pharmaceutically acceptable salt thereof.
 17. A compound of claim 15 wherein R² is —C₃₋₈ cycloalkyl, or a pharmaceutically acceptable salt thereof.
 18. A compound of claim 15 wherein R² is a heterocyclic group having 4 to 8 ring atoms selected from C, O, N, N→O, C(═O), SO₂ or S, at least one of which is O, N, N→O, SO₂ or S, or a pharmaceutically acceptable salt thereof.
 19. A compound of claim 15 wherein R¹ and R² are linked together with the nitrogen to which they are both attached to form a 4-8 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, or a pharmaceutically acceptable salt thereof.
 20. A compound of claim 1, which is selected from the group consisting of 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H—N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide; 1-[(5-Bromopyridin-2-yl)methyl]-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; N-[(1S,2S)-2-Hydroxycyclohexyl]-1-{[5-(1-methyl-1H-pyrazol-4-yl)pyriding-2-yl]methyl}-4-oxo-4H-quinolizine-3-carboxamide; N-[(1S,2S)-2-Hydroxycyclohexyl]-4-oxo-1-{[5-(1H-pyrazol-1-yl)pyridine-2-yl]methyl}-4H-quinolizine-3-carboxamide; 1-({4-[6-(Difluoromethyl)pyridine-3-yl]piperazin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; N-[(1S,2S)-2-Hydroxycyclohexyl]-1-{[4-(1-methyl-1H-pyrazol-4-yl)-3-oxopiperazin-1-yl]methyl}-4-oxo-4H-quinolizine-3-carboxylate; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1yl)methyl]-N-[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1yl)methyl]-N-[(3R,4R)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide; 1-[(4-Cyano-4-phenylpiperidin-1-yl)methyl]-N-[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; 1-{[4-Cyano-4-(3,5-dibromopyridin-2-yl)piperidin-1-yl]methyl}-N-[(3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; 1-[(4-Cyano-4-phenylpiperidin-1yl)methyl]-N-[(3S,4S)-4-hydroxytetrahydro-2H-pyran-3-yl]-4-oxo-4H-quinolizine-3-carboxamide; 1-{[4-(2-Bromophenyl)-4-cyanopiperidin-1-yl]methyl}-N-(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; rac-N-[(1R,2R)-2-Bromocyclohexyl)-1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizine-3-carboxamide; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-hydroxy-2-methylcyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-[(1R)-2-oxocyclohexyl]-4H-quinolizine-3-carboxamide; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylthio)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-{(1R,2R)-2-[(S)-methylsulfinyl]cyclohexyl}-4-oxo-4H-quinolizine-3-carboxamide; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(1R,2R)-2-(methylsulfonyl)cyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-N-piperidin-3-yl-4H-quinolizine-3-carboxamide; Methyl 4-[({1-[(4-cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-4-oxo-4H-quinolizin-3-yl}carbonyl)amino]piperidine-1-carboxylate; rac-1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-N-[(3R,4S)-3-methyltetrahydro-2H-pyran-4-yl]-4-oxo-4H-quinolizine-3-carboxamide; 1-{[4-Cyano-4-(4-cyanopyridin-2-yl)piperidin-1-yl]methyl}-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; 1-({4-Cyano-4-[4-(fluoromethyl)pyridine-2-yl]piperidin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; 1-({4-Cyano-4-[4-(difluoromethyl)pyridin-2-yl]piperidin-1-yl}methyl)-N-[(1S,2S)-2-hydroxycyclohexyl]-4-oxo-4H-quinolizine-3-carboxamide; 1-[(4-Cyano-4-pyridin-2-ylpiperidin-1-yl)methyl]-9-methyl-4-oxo-N-(tetrahydro-2H-pyran-4-yl)-4H-quinolizine-3-carboxamide; or a pharmaceutically acceptable salt thereof.
 21. A compound of claim 1, which is a compound of formula (IA)

wherein R^(A) and R^(B) are paired from the group consisting of R^(B) R^(A)

or a pharmaceutically acceptable salt thereof.
 22. A compound of claim 1, which is a compound of formula (IB)

wherein R^(A) and R^(B) are paired from the group consisting of R^(B) R^(A)

or a pharmaceutically acceptable salt thereof.
 23. A pharmaceutical composition comprising a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. 